Thin client - what it is and what it is eaten with (for example, WTWare)

• System administration

A thin client in computer technologies is a diskless client computer in networks with a client-server or terminal architecture, which transfers all or most of the information processing tasks to a server (Wikipedia).

In simpler terms, a thin client is an under-computer that loads a light operating system (usually Linux is used, in the review we will take this as a priori) and connects to a terminal server.

Typically, thin clients are created to save on hardware and software, in rare cases for other reasons.

In this article I will try to give a brief overview of WTWare, which is a Linux distribution designed specifically for thin client development.

First, about the thin client.

A thin client is a system unit that usually does not have a hard disk, and there is only the minimum set of hardware required to run the operating system of the thin client (hereinafter simply the thin client). Power, mouse, keyboard, monitor, network cable are connected to the system unit. In addition to the standard set, other devices can be connected to the thin client, provided that it can recognize them and transmit them to the terminal server.
A thin client network diagram looks something like this:

How it works:

1. A thin client is loaded on the computer from one of the sources. The main options for download sources are LAN, CD, HDD.
2. During the boot process of the thin client (or before it with the LAN option), the computer's network card is given an IP address.
3. After the download is complete, the thin client opens a terminal session via rdesktop with the terminal server specified in the settings.

1. Hardware costs are significantly reduced. An enterprise can buy old junk for a penny, and all that is needed for its work is a terminal server with sufficient resources and configured thin clients.
2. The cost of software is reduced - no need to buy software for desktops, you just need to license a terminal server (but you need to buy terminal licenses).
3. Reduced administration costs. You only need to administer the terminal server. As practice has shown, thin clients are practically not killed (if you do not make targeted efforts), and practically do not fail. But you need to understand that when changing the system administrator, he must understand this whole matter, for example, by emulating the work of thin clients on virtual machines, because any failure will lead to a general crash.

1. Download over the network. It works as follows: DHCP and TFTP servers must be raised on the local network. The computer must have either a network card with BootROM, or drivers for a network card that emulate BootROM. The network card looks for a DHCP server on the network, receives all the necessary network settings + TFTP server address. Then the TFTP server is accessed and the operating system is loaded.
2. Booting from CD / DVD / Flash / IDE is standard here, like any other operating system.

WTWare is a GNU / Linux distribution designed specifically for building thin clients. It is based on a popular client called Thinstation. The main difference is the focus on Russian users (Thinstation itself has problems with the Cyrillic alphabet), plus all sorts of minor fixes.

Configuring WTWare.

I will not talk about configuring DHCP and TFTP servers, everything is quite standard there. Let me just remind you that in the DHCP server you need to specify the address of the TFTP server, and in the TFTP server the path to the boot file and the name of this file itself.

Also, I will not delve into fine tuning WTWare, because the information on the WTWare official website is quite accessible, there is a lot of it and all of it is in Russian. I will only point out the main aspects.

So. First of all, download the Thinstation image from the WTWare website. We unpack.
The boot file is named pxelinux.0 for PXE boot (if BootROM is built into your network or motherboard) or wtshell.nbi for Etherboot bootloader (when using BootROM emulator).

By the way, Etherboot is an open source project that produces firmware for almost all existing network cards. Etherboot firmware can be written to the BootROM or flash memory of a network card, it can be run from a floppy or hard disk as a boot sector or as a DOS program.

Further, if you boot via LAN and you have correctly configured DHCP and TFTP servers, everything should work "as is". The only thing is that the terminal server will not be found, because you have not yet configured your thin clients.

If you are downloading in a different way, then it is worth reading by choosing the download method that interests you.

Configuring.

Again, I will not delve into the jungle of configuration files, because there are hundreds of parameters. you can see them full list... I will only talk about the main ones.

WTWare has following types config files:

1. all.wtc is a system-wide configuration file.
2. list.wtc - included configuration files according to the list.
3. Individual configuration files.

1. Terminal_name.wtc. The terminal name, respectively, is issued by the DHCP server.
2. ma.ca. other e.t. rm.wtc. The binding goes to the poppy address of the connected terminal.

1. all.wtc
2. Files specified in list.wtc
3. Files connected via include
4. Individual config

Configuration variables of individual files:
user \u003d username // username
password \u003d user_password // user password
domain \u003d enterprise_domain // enterprise domain

If we write a variable in an individual file that is present in common file - it will receive a higher priority.

Also, additional connected devices, such as printers, scanners, etc. are registered in individual files.

And at the end I would like to mention another interesting feature - connecting local resources (Floppy, DVD, Flash, HDD, Sound). In the config it looks like this:
floppy \u003d on
cdrom \u003d on
usb1 \u003d on
sound \u003d on
The disc will be available in the session current user from Windows Explorer at: \\\\ tsclient \\ (floppy | cdrom | usbN).

Disadvantages:

1. There may be problems with connecting equipment if there are no drivers for it in the system. I know that through some crutches you can disassemble the image, cram the driver there, assemble the image back. I have not tried it myself.
2. If the card does not have BootROM, problems may arise with the selection of Etherboot firmware (not available for all cards).

It is worth noting that the system itself is free, but you can purchase a license with a very interesting purpose - to remove the WTWare logo from the boot splash screen. As I understand it, this is done for enterprises that massively implement this product under the auspices of outsourcing.

Equipment for creating thin clients:

On the WTWare site, you can also purchase equipment for creating thin clients (so as not to collect them from trash). I must say that it (equipment) meets all the requirements of glamor. Several screenshots:

Well, that's probably all. When correct setting terminal, DHCP and TFTP servers should all work just fine. There is a lot of Russian-language literature on the Internet, so there should be no problems with setting up. And in general, in terms of documentation, I really liked the system, the manufacturer's website has almost everything.

P.S. I installed this product on my own in two enterprises, on one 34 PCs, on the second 16 PCs.
P.P.S. It should be understood that this product is not an alternative to the same Linux, and perhaps the name on each PC by the installed OS, the overall picture will be much nicer. Maybe not. This is exactly a thin client, and nothing else.

Starting from version 8.2, the 1C program got the ability to work in the thin client mode, which has limited functionality. Despite the fact that a lot of time has passed since the update was released, a large number of users still do not fully understand what this innovation is for, in what situations it is effective to use it and what is its difference. In this material, we will tell you in detail about what a 1C thin client is, about its advantages and disadvantages, as well as how to work with it.

What is a thin client?

In order to understand the functionality of a given client of the program, it is necessary to understand why it is called "thin". The answer to this question is quite simple and consists in the fact that this mode work is very limited in its capabilities, compared to the "thick" version.

The thin client of an application has a more stripped-down set of built-in language types that are solely for transferring and modifying data. Everything related to working with the database, in this case, is executed on the server. With the help of this version of the application, a managed 1C interface is developed, which allows optimizing the work of the company.

"Thin clients" 1C are able to receive ready-made data through a web connection, which have already been prepared in advance by the server.

In addition, the use of this type of application is possible using one of three technologies:

• Via the web (using an internet connection);
• Via TCP / IP (client-server type);
• Directly with the database.

Internet connection

The "thin client" has the ability to interact with the "1C: Enterprise" program using a web connection to the Internet. In this case, work occurs with a specially configured web server using the http data transfer protocol. Nevertheless, the web server itself works with the 1C: Enterprise program via the TCP / IP protocol or directly.

Important: one of the following systems must be used as web servers:

• Apache;

Client-server connection

In this case, "thin clients" connect to the servers directly using the TCP / IP data transfer protocol.

Direct database connection

In this case, the client interacts directly with the application database. To organize this scheme of work, a special environment is created on the computer on which the client is installed, which from the point of view of the program is perceived as a server. In order to organize it, you must:

• Download the required server files to your computer;
• Load application configuration.

Thin client benefits

If we set aside the process technology and move on to the direct advantages that the use of this version of the 1C client gives, we can highlight several serious advantages. These include:

• Mobility;
• Reducing the load on the communication channel;
• Minimum system requirements;
• Reducing company costs.

Mobility

The hardware "thin client" allows the user to be anywhere in the world, if there is an Internet connection. For example, suppose the head of a department is on vacation abroad. In order to make any important decision, he needs to familiarize himself with the latest reporting data. The full version of the application requires a mandatory local network connection, which is why a "thin client" comes to the rescue in this case. It allows you to work with the database if you have regular connection to the internet.

Another example. Sometimes, when making transactions in any department that does not have a connection to the local network, for example, at a company's warehouse, it is necessary to download data from the warehouse database for subsequent uploading to the accounting department.

Of course, such manipulations are time consuming and inconvenient. Thin clients are used to simplify these tasks. If you have a web connection, you can easily transfer data to common base 1C data directly from the warehouse.

In addition, thin clients use the network channel exclusively for data transmission. The full-fledged version of the application also uses it to transfer service data necessary for the software to work, which reduces the useful bandwidth of the channel.

Thus, "thin clients" allow you to work in the 1C program where there is no web connection with good bandwidth.

Low system requirements

The situation is similar and system requirements programs. For the full version to work, more powerful computers are needed, since the application uses the processor and RAM of the system. "Thin clients" 1C is much less demanding on the resources of a personal computer. This is what makes it possible to use it even on weak systems.

Reducing company costs

This point follows from all the previous ones. Due to the fact that the development of a managed interface allows you to optimize the workflow, save time and resources of the company, this leads to a decrease in the total costs of the company for bookkeeping.

Disadvantages of a "thin client"

Of course, any medal has a downside. The "thin client" also has some inconveniences and limitations, which cannot be ignored. These include:

• The requirement for a powerful server;
• Limited functionality;
• Unusual interface.

Powerful server required

In the event that a large number of "thin clients" interact with the main server via a web connection, a rather large load falls on it, which imposes certain technical requirements... However, the use of the full-fledged version of the program does not load much less, therefore this drawback is very relative.

Limited functionality

As mentioned above, the light version of the application has very limited functionality. So, for example, there is no possibility to work in the “Configurator” mode.

Interface

This disadvantage over time and with the release of updates, it gradually fades away, but at first many companies abandoned the use of "thin clients" or tried to avoid it precisely because the application interface was extremely inconvenient and very different from the full version.

Thin clients are devices (terminals) that do not have their own computing power, are connected to a server common to all users and are capable of displaying information. In other words, they are diskless compact personal computers (diskless thin clients), to which ordinary peripheral devices are connected - keyboard, mouse, monitor, acustic systems etc.

Thin clients with a terminal server are connected via a local network or dial-up connection (modem). All programs and applications necessary for your work are installed on the server. It also stores data and performs all calculations.

In other words, windows terminals are used to display the data transmitted from the server on the monitor screen and to send the data received from the input device to the server. In this case, the user, no matter what terminal he is working with, will perceive it as his own computer, since on the monitor screen he will see exactly his desktop and his documents.

When transferring an office to thin clients, load balancing falls entirely on the terminal server, and each user works at a separate input-output device (terminal stations), which does not perform any calculations by itself, but only serves to define tasks and receive answers. Terminal workstations are able to dispense with any piece of hardware or software deemed essential for "regular" computers.

What tasks are solved when implementing thin clients?

The conventional personal computer in the workplace is still practically the standard, although in most cases it is absurd. Thin clients do more than just solve technical problems, but also to overcome the prevailing stereotypes.

The obvious advantages of using terminal clients instead of conventional personal computers are as follows:

- reduced initial acquisition costs due to minimal configuration requirements;
unification - all clients have the same set of software;
- simplicity of tasks implementation - there is no need to configure each computer separately, since the information process is centrally controlled. The system administrator performs all settings for managing thin clients centrally on the server;
- saving time system administratorserving exactly the same computers, the probability of breakdowns is minimized, and all programs are installed on the server;
- scalability - the image of the system created once for the entire group of users allows you to maintain an easily scalable network. You can install as many PCs as required, while adding new jobs requires minimal effort;
- security and resiliency. The terminal, while loading, receives the operating system "from the manufacturer", which is configured only by the information support department. All modifications of the operating system and application software do not affect either other users or the image stored on the server. All user information is stored on the server on a RAID array and is regularly backed up, which increases fault tolerance;
- protection against information leaks - no local media - no way to make copies of documents on removable media.

Terminal cost is always lower than cost workstation, but at the same time, the user has access to a significantly greater computing power of the server to which he is connected.

An important aspect is the use of legal software and significant savings in the cost of its acquisition. In most cases, a minimum number of application licenses are required because the programs installed on the server can be run by all users and uses a single embedded operating system.

Consumed electric power a diskless thin client (windows terminal) is tens of times less than the capacity of conventional work terminal stations. Moreover, the efficiency of using terminal solutions directly depends on the number of stations - the more thin clients are used, the more cost-effective the entire system is. On the other hand, to increase functionality and performance, you do not need to update the entire fleet, you can simply upgrade the server. Thin client is quiet and does not heat up the environment.

Since the correction of errors and installation of programs in the terminal system is carried out centrally on the terminal server, the administrator of the local network can easily use a remote session with the user. Administration does not require setting up the software package directly at the user's workplace; less working time and personnel are required.

Even large-scale enterprise IT infrastructures can be served by one or two administrators. Replacing a failed thin client or installing a new one can be performed by personnel with no special training. All programs and user data are located on the terminal server, so a failure at the user's workplace will not entail data loss, which means it will not entail downtime.

There are known performance issues with older systems that use file server technology. With the growing volume of transactions and the number of clients, the local network becomes a bottleneck. Terminal solutions allow avoiding the transmission of a huge amount of information over the network, since the client's tasks are performed on the server where the disk system is located.

Moreover, since all programs are installed centrally in the terminal system, the simultaneous transition to new versions occurs at the same time and without modernization of workplaces, including for employees geographically located in different offices.

On the other hand, an obvious advantage should be noted - a significant increase in the level of data protection. For example, if the administrator disables I / O ports, unauthorized information retrieval is impossible. And the differentiation of access to data and programs is carried out by system means on the server. Encrypting network traffic allows you to achieve the maximum level of information protection.

The concept of thin terminal clients is not new. Indeed, why equip workplace user with relatively productive hardware, purchase a license for the client OS, install application software, antivirus, ensure the proper level of protection of the workstation and data, if the user performs all his operations on the terminal server, in fact, without using local resources (except peripherals). In this article, we will briefly review the domestic solution for organizing thin terminal clients - WTware.

WTware Is an optimized Linux distribution that includes all required drivers and clients to connect to terminal windows servers (rdesktop), Linux (xrdp), Hyper-V VDI, Mac Terminal Server.

Main advantages of WTware:

• Low hardware requirements. WTware can be run on almost any computer with at least 48 MB RAM (requires 64 MB for optimal performance). For Raspberry Pi 2 exist free version WTware (http://winterminal.com/ru/)
• It is not necessary to run the client hDD... Both network booting and booting from any media are supported
• Easy to install and configure the client side, does not require the administrator to have knowledge of Linux administration
• Centralized terminal configuration management
• Support for a wide range of equipment. Possibility of forwarding local printers, barcode scanners and other peripherals to the terminal session
• Support for remote connection to the terminal console by technical support services (via VNC)
• WTware is a Russian product, which means that all documentation and technical support is also provided in Russian.
• Ability to simultaneously connect to 4 terminal servers (switching between sessions using the combinations Win + 1 - Win + 4)

Let's consider the “quick” start procedure for using WTware solution to organize a workplace with a thin terminal client in a typical office network.

WTware client download options

Before you start configuring and deploying WTware, you need to choose the preferred way of loading thin clients. WTware can boot from almost anything, be it:

• HDD
• CD-Rom
• Flash drive
• Diskette
• Network card with BootROM

In most cases, it is preferable to use network boot because this greatly facilitates deployment and centralized client management. This is the boot option that we will consider.

Note... If you need to connect to the terminal single clients from remote offices connected via slow communication channels, you can use booting from physical media for them. If there are several clients and any server in such offices, you should nevertheless consider deploying your own WTware TFTP server on it.

Also note that the manufacturer's website indicates the ability to download terminals via HTTP, which should reduce the TFTP load with a large number of clients (more than 300) and improve downloads on slow and unreliable communication channels.

Boot processWTware

To run WTware client on a user's computer, you need:

• Download distribution binaries from server (via TFTP) or local media
• Get network settings from DHCP server or from local configuration files
• Get the configuration file from the server (via TFTP) or load it from disk

WTware server part installation

Let's start with the installation of the server part of the WTware system. In our case, it was decided to install it on a DHCP server running the OS.

Download the distribution kit from the developer's site - at the time of this writing, the version of wtware.5.4.8.ru.exe (226 Mb) and run the installation.

Specify the path for installing configuration files (by default, C: \\ ProgramData \\ WTware) and the program itself (C: \\ Program Files (x86) \\ WTware).

• Service WTFTP - required for booting over the network, keeps a log of calls and allows you to diagnose problems
• Service WTUSBIP - WTware USBIP Initiator service is used for automatic connection USB terminal devices
• Services WTDHCP - assigns IP addresses to terminals, it is necessary for booting over the network

Because we will use our own DHCP server already, so we will not install the WTDHCP service. MS DHCP server configuration is described in the section.

Advice... If your network has not yet deployed a DHCP server, it makes sense to use the built-in WTware DHCP servers (WTDHCP). Using WTDHCP allows you to quickly deploy and run a DHCP service for a small network. The WTDHCP service is configured during installation and later with the help of a graphical utility - WTware configurator (win32.exe), the capabilities of which are discussed.

Note... In the event that your network is divided into segments, each of which will have thin clients, there is no need to raise its own DHCP server in each. One server can serve a large number of zones (subnets). Forwarding DHCP packets between segments is possible via.

We start the installation.

After installing WTWare, two additional services will appear in the system:

• WTwareTFTP - executable file C: \\ Program Files (x86) \\ WTware \\ Bin \\ wtftp.exe - uses local UDP / 69 port
• WTware USBIP Initiator - C: \\ Program Files (x86) \\ WTware \\ Bin \\ wtusbip.exe - TCP / 780 port

Configuring DHCP Server Options

It is assumed that a DHCP server is already deployed and used in our network on any server edition of Windows. We launch the DHCP management console (dhcpmgmt.msc) and find the DHCP zone we are interested in (in our case, the zone name is Managers). We need to write additional zone settings required for network booting of diskless terminals.

In the zone settings, you must additionally specify two parameters:

• 066 (Boot Server Host Name) - here you specify the ip address of the server on which the WTware TFTP server will work (in our case it matches the DHCP server address)
• 067 (Bootfile Name) - the file from which the terminal loading should start is specified here. To boot using PXE (if BootROM is built into your network card or motherboard by the manufacturer) the parameter value is set 5.4.8 / wtware.pxe ... The wtware.pxe file is located in the 5.4.8 subdirectory of the tftp server root (by default, the tftp root is located in the C: \\ Program Files (x86) \\ WTware \\ TFTPDROOT \\ directory)

Note... For the Etherboot loader (when using the BootROM emulator), you need to specify another file as the value for option 067 - 5.4.8 / wtshell.nbi

After configuring these two parameters, the DHCP server provides the client with all the information it needs to boot over the network.

Note... In the event that the WTWare terminal will be installed on a USB flash drive or local disk, you can prevent users from changing the configuration of their station. To do this, you need to password-protect WTware Setup menu. To do this, you can use another DHCP zone option - 018 (Extensions Path). This field indicates the password hash obtained using a special utility. The purpose of specifying a hash is to prevent the transmission of a password in clear text in a DHCP response.

Configuring WTWare Terminal Settings

Configuration of WTWare terminal clients using network booting is performed using configuration files. Client configuration is formed from three files:

• System-wide configuration file all.wtc (C: \\ Program Files (x86) \\ WTware \\ TFTPDROOT \\ Everyone)
• Personal config file config.wtc (stored in the personal directory of each client, identified by MAC address, for example (C: \\ Program Files (x86) \\ WTware \\ TFTPDROOT \\ Terminals \\ 00.50.56.BB.AD.80)
• Include files defined in the file list.wtc

In the all.wtc file, you need to specify the parameters that are the same for all terminals.

For example, you can set the addresses of terminal servers available for connection by specifying their IP address

server \u003d 10.24.181.44

or DNS name of the server (provided that clients get the address of the name server on the network via DHCP)

server \u003d msk-term-1c.site

Or, you can let the user specify the name of the terminal server to connect to.

Note... By default, the RDP client is launched on the client, but it is possible to launch it on the browser thin client Google chrome... In this case, the client must have at least 512 MB of RAM, and the configuration file contains following lines (we will also set the proxy server address for the browser):

application \u003d chrome
chrome_proxy \u003d 192.168.1.23: 3128

To immediately open a specific application on the terminal server instead of the desktop, you need to specify the shell parameter in the configuration file:

For example, to run the Directum client, you need to specify:

shell \u003d C: \\ Program Files (x86) \\ DIRECTUM Company \\ DIRECTUM 5.1 \\ SBRte.exe -S \u003d msk-drc01 -D \u003d DIRECTUMDB

Individual configuration files for each client are stored in the C: \\ Program Files (x86) \\ WTware \\ TFTPDROOT \\ Terminals \\ directory. A personal directory with its MAC address is created for each client. It is in this directory that the client will look for the config.wtc file with its configuration.

The developer's site presents more than these and other parameters of the configuration files.

Setting up and working with the WTWare client

So, setting up the server side is finished, let's move on to setting up the client. In the BIOS / computer that will be used as a thin client in the section in which the brute force is configured boot devices, specify the highest priority for network boot from PXE (Network boot, LAN boot).

We save the changes and reboot the system. If everything is configured correctly on the WTware and DHCP server side, the client should receive an IP address from the DHCP server and, according to the parameters we configured, perform a network boot from the specified one.

At the first start, you can configure the terminal (F10 - terminal setup wizard).

We will be prompted to select a video card driver and other display options. The preferred settings can be saved to the client's personal configuration file on the server. In this case, next time you will not need to manually edit the display settings.

To do this, on the TFTP server in the C: \\ Program Files (x86) \\ WTware \\ TFTPDROOT \\ Terminals \\ 00.50.56.BB.AD.80 directory (a directory with a name containing the client's MAC address), create a config.wtc file, in which the client settings are specified:

video \u003d VESA (F)
bpp \u003d 16
display \u003d 800x600

On the next boot, the terminal will automatically boot with these parameters.

If the terminal server address is specified in the configuration file, the WTWare client automatically initiates an RDP connection. It remains to log in to the server and its desktop will open in front of us.

If the configuration file provides the ability to independently select a terminal server, the client can specify it manually.

To diagnose the work of clients, a small web server operates on each terminal. To open the diagnostic page, just enter the client's ip address in the browser. On the web page that opens, you can view the current client settings, the state of its components, logs, shutdown / restart buttons, etc.

By default, access to this page is not restricted. To allow connecting to the web server only from certain addresses, you need to specify the line in the configuration file:

httpd \u003d 10.10.1.55, 10.10.1.56

Graphic configurator WTware

In addition to control via text configuration files, it is possible to manage system settings and client terminals from a separate graphics application - WTware configurator (C: \\ Program Files (x86) \\ WTware \\ Bin \\ win32.exe), which makes it more convenient to work with text config files.

What you can use this utility for:

In most cases, using the configurator is preferable to manually editing configuration files, since simplifies navigation through the structure of configuration files and reduces the likelihood of errors.

WTWare Licensing and Pricing

WTWare licenses are tied to the MAC address of the computer's network card. All licenses must be written to the server in the wtware.lic file.

The cost of a WTWare license for one workplace depends on the number of clients and starts from 1000 rubles (with the number of clients from 1 to 9) and ends with 350 rubles (when purchasing more than 100 licenses).

conclusions

WTwareleaves the impression of a high-quality and solid product that allows you to deploy thin terminal clients without significant costs. The solution from WTware impresses with its simplicity and simultaneous flexibility in terms of centralized administration and deployment. And the low cost of licenses almost immediately leaves all competitors behind.

Of the free analogs of WTWare for organizing a thin client, you can recall Thinstation, but the latter loses significantly in manageability and is much more difficult to deploy.

Cycle law:
The story develops in a spiral.

This statement, familiar to us from school, from general philosophy is also applicable to computer technology... Let's go deeper into history. In the beginning there were mechanical abacus with knuckles, then mechanical computers appeared. Later, vacuum tubes and the first large computers based on them appeared, which occupied entire buildings. Then the transistor was invented, may its name be glorified. Note that the word "transistor" in those days meant far from one of the many cells on a silicon plate, each of which is no more than 0.18 microns in size, and millions of them are placed on a plate with an area of \u200b\u200ba square centimeter. No, the transistor was a solid radio component in a separate case with dimensions of at least a centimeter. But it was still a breakthrough. As a result, relatively compact computers appeared, occupying "only" a few cabinets and possessing a crazy, at that time, speed. In addition to their huge size, they had another important drawback - the price. Therefore, such computers were inaccessible to everyone who wished. I had to use computers together. First, in time-sharing mode, one by one. And when keyboard input and displays were invented, as well as multitasking operating systems (OS), it became possible for many users to work simultaneously on the same machine. That is, at the workplace there was only a terminal - a keyboard for entering data and a display for displaying them, and all information processing took place on a mainframe.

But science did not stand still, microcircuits became smaller, and the cost of their production decreased. As a result of this rapid progress, we have come to affordable and powerful personal computers that almost everyone owns. Relatively inexpensive. After all, if you add up the costs of an organization that needs 20, 50 or more machines, then add here the cost of the software installed on them, plus the costs of people serving these computers, and we get a very big figure.

It was not for nothing that I mentioned that modern personal computers (PCs) are very powerful. Indeed, for most office and corporate tasks (such as MS Office, 1C Accounting, Sail, using Internet Explorer for WEB surfing, email etc.) high power is not needed. But looking into the PriceList of any solid computer firm, we can hardly find a typical computer configuration with a processor frequency below gigahertz. But on average (in typical office tasks) it will be loaded by only 10-15 percent. Moreover, sometimes a bottleneck (this is with such modern and fast computers) becomes the network bandwidth. A good example of this is the clients of 1C Accounting, who generate a lot of network traffic when accessing the database during their work.

In addition, no matter how modern a computer bought today may seem, after 2-3 years it can hardly handle new software (software). Therefore, an outdated computer has to be upgraded or, simply put, changed to a new one.

This is why thin clients have become more popular over the past few years. What is a thin client?

In a nutshell, it is a self-contained diskless device with a power source to which input devices (keyboard, mouse, smart card reader, etc.) and information output devices (monitor, printer, speakers, etc.) are connected. The device is intended for input information and sending it to the server, as well as to display information received from the server. The terminal is connected to the server via a local Ethernet network, via a modem or via serial communication lines. The server must have a multitasking and multiuser OS installed and the server must be powerful enough (compared to the terminals connected to it). In general, the thin client itself does not process information; all calculations take place on a remote server. That is why the power requirements of such devices are low. In principle, even 286 and 386 computers can serve as a thin client, on which you can install DOS or Windows 3.11, as well as the program itself for connecting to the server. As a result, we get a high-speed machine running Windows 2000 (if the server has this operating system installed) to work in typical office tasks.

Now let's draw parallels. A network of autonomous terminal devices connected to a powerful server computer. The terminals only receive data from input devices and send them to the server, and also display the data received from the server on the monitor. All information is processed on a remote machine - a terminal server. Yes Yes. It is the computing centers of the 70s with mainframes that come to mind. Of course, these are no longer monochrome displays operating in text mode. On the table is not only the keyboard, there is a sound. And the range of tasks performed has expanded. But the idea remained the same.

Of course, the thin client market is not limited to the family operating systems MS Windows. But thanks to the prevalence of products such as MS Office and of course MS Windows with IE, the ubiquitous Windows is installed in many organizations. That is why many are interested in terminal solutions based on this OS.

There are two protocols on the market for interaction between thin clients and terminal servers. The first, ICA (Independent Computing Architecture) from Citrix, appeared on the market a little earlier. The second, RDP (Remote Desktop Protocol), was developed by Microsoft and ships with Windows NT TSE, Windows 2000 Server and above. ICA is considered to be more universal, and its support is not limited only to win32 versions of Windows operating systems. It also supports different versions * nix OS, Macintosh and even Java clients. As for the rest, by now the functionality of both protocols is practically equal. Although there is an opinion that Citrix provides more freedom and convenience in terminal network administration.

I will try to summarize the pros and cons of the terminal method of building a network (in the case using windows OC).

• Any terminal is analogous to a powerful workstation.
  After all, all programs are executed locally on a high-speed terminal server.
• Saving money both on the cost of the thinnest client and on the cost of software.
  Indeed, the cost of the terminal is slightly lower than the average workstation. Software it is installed only on the server computer, although it can be used by all terminal owners (or some, depending on access rights).
• Ease of increasing computing power.
  There is no need to upgrade the terminal. Since it is only a device for input and display of information, without processing anything itself. If there is a lack of computing resources, it is enough to upgrade the server (usually it is more profitable than upgrading N full-fledged workstations), and new resources will be available to all terminals at once.
• Reduction of the work park for the network administrator.
  After all, you will have to administer only one server, and not N workstations scattered throughout the office (s) of the organization.
• Ability to access your virtual desktop and all documents from any terminal connected to the server.
  Since all information is stored on the server, it is enough to authenticate in the system (enter your username and password) from any terminal.
• No problems with power outages.
  Since all information is stored on the server, it is enough to equip it with uninterruptible power supplies. Loss of energy in the workplace will only lead to a temporary inability to see what is happening on the terminal screen. Here we can give the following analogy - after all, when the monitor is turned off, nothing happens to open source programs? After energizing (or when the terminal is turned on again), the user will return to the state of running programs that remained at the moment the terminal was turned off.
• Acceleration of some programs with increased demands on network bandwidth.
  Good examples of such programs are 1C Accounting and Parus. When its server and client parts are located on the same machine, a bottleneck is eliminated - sending data over the network when clients request to the database, and the programs begin to run much faster.
• Good security implementation.
  Again, all files are located on the same server, there is no information on thin clients, access rights are differentiated using system means. The user cannot upload information to a floppy disk, since floppy drives are usually absent or access to them is limited. That is, you only need to protect the server itself, but physically it and the terminals can be geographically far from each other, for example, in neighboring buildings.
• Rapid deployment of a new workplace
  You can even connect a thin client from your home, just connect it to a terminal server (for example, via the Internet). The preliminary and one-time setup takes only a few minutes of time, after which we immediately get to our workplace, with already installed programs (on server).
• Quiet operation
  Terminals usually do not have mechanical components such as hard drives and fans (cooling is carried out passively), therefore they do not produce noise at all.
• Low power consumption of the terminal
  The architectures used have low power consumption. For one computer, this may not be noticeable. And if there are 100 of them?
• Longer MTBF.
  The absence of mechanical components, as well as the simplified architecture itself, increases the reliability of the system as a whole, which is important, given the much longer service life of the terminals compared to workstations.
• Small size and ergonomics
  Thin clients have this name for a reason. They are usually no larger than a large book and do not take up much desk space.
• You have to work at work.
  You will not be able to play 3D games or watch movies. Firstly, they will not be on the server and it will be impossible to install them yourself (due to restrictions, set by the administrator for installing additional software). Secondly, the network bandwidth will not be sufficient for an acceptable screen refresh rate for these applications.

Minuses. back side medals are also present.

• The thin client is not a panacea for everything.
  Terminals are not designed to perform heavy tasks involving complex calculations (for example, AutoCAD and other modeling systems) or generating a lot of traffic for transmission to the client (for example, watching videos). In the first case, this is due to the high load on the computing power of the server (it will be able to serve very few clients), in the second - to the network bandwidth. In this case, you need to use full-fledged workstations. By the way, modern 3D games fall into both categories at once.
• You still have to pay.
  The lower cost of the terminal is offset by the higher cost of the server. After all, this machine must be powerful enough to perform the tasks of many thin clients connected to it. For the sake of fairness, I note that the dependence of server capacity on the number of working clients is not linear. Most of the typical tasks (for example, several copies of MS Office in memory) use the libraries of the already running first copy for their work, so the needs for random access memory will be relatively low.
• Server OS - MS Windows.
  With all the ensuing consequences in the form of considerable requests to server performance only for the OS's own needs. But it can be scaled by distributing the client load over several servers in the case of MS Windows Advanced Server or Data Center.
• In general, everything works on one server computer.
  Therefore, all possible measures must be ensured for its trouble-free operation and data safety.
• The need for a constant communication channel
  In some cases, it is not necessary for a workstation to have a permanent, much less fast, communication channel. The terminal needs constant communication with the server. On average, you need a channel with a bandwidth of at least 20 Kbps.

In summary, the benefits of thin clients are attractive enough to be used in many organizations. You just need to clearly define for yourself the pros and cons of the terminal approach. It is also important to note that although the low cost of thin clients can be offset by the high cost of the server side, the total cost of ownership (TCO - Total Cost of Ownership) turns out to be significantly lower (according to the Gartner Group - by 5-40 percent) when used in workplaces. thin clients, not full-fledged computers. After all, TCO consists not only of the cost of purchasing equipment, but also of the administration of this equipment, the cost of modernization. This also includes losses incurred due to hardware failures.

As a vivid example of a terminal solution, consider a thin client from a Russian company.

The photo shows appearance (shot using a blue filter) AK Windows of this company's GP terminal. Note - this russian company... The price of such a thin client is only about $ 300 (at the time of publication), which is significantly lower than Western counterparts. People familiar with the level of prices for old components may object: while assembling a Pentium-class computer] [you will have to spend only $ 200, and even a Pentium costs a penny in general! Yes, but do not forget that in the case of our own assembly, we will get exactly a personal computer operating in terminal mode. With a large body size, power consumption, hard disk, coolers and the resulting noise, old components, etc. And with the resulting reliability. Thin clients were originally designed specifically for their own range of tasks, do not have mechanical parts and are potentially more reliable. Do not forget about technical support - we live in Russia - the company is nearby.

GP terminal AK specifications.

The attentive reader has already noticed that the processor frequency of the GP thin client is only 300 MHz. In fact, more is not needed, because the terminal is practically not busy with information processing. However, the company also offers models with a higher processor frequency based on the VIA C3 processor.

Inside view

The back panel of the terminal with interfaces looks like this:

And inside the case there is only one motherboard, on which all element base devices.

A 16 MB flash drive is used instead of a hard disk. From it, the initial boot of the Windows CE OS is performed. It is her windows that are visible on the screen before connecting to the terminal server.

At the heart of the system is the National Semiconductor GX1 processor. This is the first chip of the company, created using 0.18 micron technology and having a very low heat dissipation - 0.8-1.4 W, depending on the operating mode. The processor was originally intended for installation in various terminal systems, Internet consoles, etc.

The processor core is built on the basis of the x86 architecture, it includes blocks of arithmetic with fixed and floating point and has a cache of the first level of 16 KB. The processor integrates a VGA controller with a 2D graphics accelerator and additional buffers interfaces to external controllers for playing MPEG1 video. The processor also has an integrated controller SDRAM memory and pCI bus... The chip also supports the MMX instruction set and can operate at frequencies from 200 to 333 MHz. The processor has built-in basic support for audio functions (some of them are taken over by an external controller). Due to the low heat dissipation, only passive cooling of the processor (radiator) is used.

The role of the south bridge is performed by the CS5530A (PCI-to-ISA bridge) chip. It also integrates two IDE controllers and a USB bus for two ports. In addition, the CS5530A connects to the GX1 processor's video controller interface for additional video acceleration and output to analog or digital displays. The CS5530A also has a built-in interface for connecting an external AC "97" audio codec. The microcircuit is low power consumption and low heat dissipation.

To support other I / O functions, a PC97317 controller from the same manufacturer is used, connected to the south bridge. PC87317 is a single-chip controller for most standard ISA / EISA / MicroChannel peripherals. The chip contains an advanced Real-Time Clock module, a floppy disk controller (FDC controller), a keyboard and mouse controller, two serial ports (UARTs) with infrared communication (IR) support, an IEEE 1284 parallel port controller, and several more controllers.

The terminal itself is assembled in a small case and, as you can see in the photo of the board, does not have any mechanical moving elements such as fans and hard drives. Therefore, we can safely talk about the zero noise level during the operation of this terminal.

Preparing for the first launch

You need to install MS Windows NT TSE or Windows 2000 server (or higher) on the server. Additionally, you should install the terminal services service in the installation panel near the removal of OS components. After that, you just need to create the required number of user accounts.

Setting up the thin client itself is very simple.

When you first start the terminal, it will display the setup wizard prompts. It can be used to set a fixed or dynamic client IP address.

The DNS and WINS server addresses and the presence of a local printer (connected directly to the terminal) are optionally set.

The same wizard allows you to set the resolution and refresh rate of the monitor screen. After that, the wizard proceeds to setting up (setting) the remote terminal server and its parameters. Moreover, nothing prevents you from creating several records to different servers and then switching between them.

First, you need to select the type of connection protocol - RDP (native to WinNT TSE / Win2K Server protocol) or ICA (from Citrix). The second is more versatile, but in our case it has more options. To use it, the server must have Citrix MetaFrame software installed. The terminal can be connected both via a local Ethernet network and via a modem. I think the latter is exotic. After all, an analog modem cannot provide an acceptable speed of information transfer from the server and, accordingly, comfortable work at the terminal is out of the question.

The setup procedure is similar for both types of protocol. At a minimum, you will need to enter the IP address of the terminal server and, possibly, the username and password, if required automatic login into the system.

If the ICA protocol is used, you can activate traffic encryption and select the terminal operation modes through the firewall.

After installing all required parameters the terminal configuration can be considered complete. You can connect to the server and start working.

The setup procedure is one-time (for each server record) and takes no more than five minutes. Agree, this is much faster than installing an OS with all the necessary programs on a full-fledged workstation.

The settings specified in the initial setup wizard can always be changed later via the terminal setup panel. You can also set other specific options here, for example, adjust the sensitivity of the mouse and keyboard,

and also modify the display parameters and the terminal IP address.

You can also set up a printer connected to the terminal, set the local date and time, set up a dial-up connection (using an analog modem).

The service for updating the firmware (internal OS) of the terminal is presented in the Firmware tab. The firmware can be taken from a file or from a remote FTP server. Well, so that users do not have access to the terminal settings panel, you can set a password on it or hide the panel altogether.

As you can see, setting up the terminal is simple and does not take much time. After connecting to the server, the user finds himself in a familiar Windows environment and can start working. The main administrator's time will be spent on configuring the terminal server itself (or servers, in the case of a large fleet of thin clients).

Testing

I believe that one of the critical parameters of the terminal's operation is the minimum bandwidth at which work on it will be more or less comfortable. I conducted several tests limiting the bandwidth between the server and the thin client at 4, 8, 16, 20, 24 Kb / s using the RDP protocol. Of course, it is impossible to draw objective conclusions, so what is written below can be considered my subjective perception.

It is inconvenient to work at 4 and 8 KB / sec (especially when it comes to 4 KB / sec) - windows open and move with a noticeable delay, while typing, there is often a feeling of a sufficiently large buffer in the keyboard (letters do not appear immediately and not one by one, but in groups of 5-15 characters. Plus, the initial connection of the terminal to the server with a channel of 4 Kb / s takes considerable time. At 16 Kb, the above effects are almost completely eliminated, but still some lag (delay) is noticeable when dragging and opening windows On a channel of 20 Kb / s and higher, working at the terminal is quite comfortable.

Note that, judging by the reviews of third-party sources, on slow lines, a big gain in speed is obtained when using the ICA protocol. It can work even on modem communication lines. Unfortunately, I did not have the opportunity to test the operation of the terminal on this protocol, in the next review this defect will be eliminated.

conclusions

Give preference to full-fledged workstations or thin clients - each manager decides for himself. In this article, I just wanted to show that for some classes of tasks, terminals are more beneficial not only in terms of convenience, but also allow you to more economically spend cashallocated for the organization's computer equipment.