The first ibm computer. Personal computer such as IBM PC. Logic diagram. program working window

General information about MS DOS

Operating systems for personal computers during the existence of this class of computers since 1975 have undergone significant development, accompanied by an increase in the bit capacity of personal computers (PCs) from 8 to 32, expanding capabilities, improving the user interface (Table 2.1).

Table 2.1 Some types of OS for personal computers

8-bit operating systems retain their importance as the operating systems of the simplest educational and household (gaming) computers. Due to limited address space random access memory(65 kb) serious professional use of such computers is impossible.

16-bit IBM-compatible computers make up a significant part of the professional personal computer fleet in our country. The most common operating system for these computers is a single-user single-tasking MS DOS (from MicroSoft - abbreviated to MS; DOS is an English abbreviation of the name "disk operating system"). The first version of this OS was created simultaneously with the personal computer IBM PC in 1981 and from external devices only supported floppy disks with 160 kB floppy disks. Version 2.0 is associated with the appearance of the PC XT modification, it also supported drives on hard drives up to 10 MB, tree-like file structure. Popular over the years version 3.3 (1987) - to support PC AT. This OS modification addresses 640 KB of RAM, which at the time of its appearance was a progressive moment, and then became a factor holding back the progress of software. Modern versions of MS DOS have overcome the limitations on the size of random access memory (RAM), have many new commands, contain built-in device drivers, a graphical shell, help system etc.

The main structural components of MS DOS are as follows:

Basic Input / Output System (BIOS);

Boot Loader (SB);

Device drivers (i.e. programs that support their operation);

Basic module;

Command processor (also called command interpreter);

DOS utilities (auxiliary programs).

Let's briefly describe the main components. The BIOS is stored in ROM. This program is written directly in machine codes; when the computer is turned on, it is automatically read into RAM, launched for execution and makes a cursory check of the operability of the main devices of the computer. The BIOS then searches the disks for the startup program operating system(boot programs). BIOS also has functions to support standard peripheral devices, primarily the display and keyboard.

The bootstrap program found by the BIOS on the disk accesses drives A, B, and so on in sequence. until it finds the SB program - bootloader... This program checks for the presence of the operating system kernel on the disk, which consists of files named ibmio.sys - the BIOS extension file and command.com - the command processor, loads them into RAM and launches the first of these programs for execution. It additionally tests hardware, performs DOS configuration (standard in the absence of a config.sys file - a configuration file or non-standard in accordance with the contents of the config.sys file), connects the necessary drivers, etc. Next, this program sets some instructions on how to handle interrupts (interrupt vectors) and transfers control to the base DOS module, which continues to set the rules for processing interrupts and then loads the command processor into RAM and transfers control to it.

A user working with DOS without shell programs or additional interface systems communicates directly with the command processor. The operating mode is interactive, i.e. the user issues a command, the OS executes and waits for the next command. The way to issue commands is quite archaic - you just need to type the text of the command on the keyboard, for which you need to remember most of the commands, and for rare ones - use the reference book (either in the form of a book or built into DOS).

The command processor, when launched, first searches for and executes the auto-run program (autoexec.bat file), if any. This program is created by the user from DOS commands in order to perform some routine actions to create a comfortable environment to get started. For example, if you get the Norton Commander panel on the screen when you start your computer, it’s only because this program “auto-start” is provided for by those who compiled the autoexec.bat file. The next action of the command processor is to issue an invitation to the user to enter a command on the screen, which looks, for example, like this: C> (if DOS was loaded from the C drive).

During the operation of application programs, only a small part of DOS (called resident) is constantly in RAM. All other DOS modules are loaded only as needed and removed from RAM after processing.

The MS DOS file system supports drives designated by a Latin letter and a colon, for example:

a hierarchical directory system borrowed from the UNIX system, files with names of up to eight characters and an extension of up to three.

Common MS DOS Commands

Common commands are recognized and executed by the command.com shell. Commands are entered from the keyboard; their entry is completed by pressing the () key.

Common DOS commands are divided into groups:

Disk commands;

File commands;

Directory commands;

System control commands.

A typical command structure looks like this:

Parameters (arguments) indicate those objects on which operations are performed, keys specify the action of the command. The sign of the key (switch) is the presence of a slanting line "/". Square brackets indicate the possibility of missing a fragment.

The command for working with directories; displays a list of directories and files within the current directory. If you use the DIR command without parameters and switches, it displays the names of files (directory), their extensions, sizes (in bytes), date and time of creation, their number, total size and size of free disk space.

The complete syntax is:

DIR [drive:] [path] [filename] | / P] // W] attributes]] sort_order]] [...]

Options

[drive:] [path] indicates the drive and directory for which you want to view the table of contents;

[filename] indicates the file or group of files to be listed.

Placeholders can be used in the file name:

Replaces one arbitrary character in the file name;

* replaces an arbitrary number of arbitrary characters.

For example:

DIR * .txt view the list of all files with the txt extension;

DIR a?. * View a list of files with names of two characters, the first of which is the letter a, and arbitrary extensions.

/ P displays information until the screen is full, to get the next screens you need to press any key;

/ W displays information in abbreviated form, only the names of files and directories (in 5 columns);

/ A [[:] attributes] displays information on those directories and files, the attributes of which are specified.

Here are some of the attributes:

N. hidden files;

All files except hidden ones;

S system files;

S all files except system files;

D directories;

D files only;

R files are read-only.

Parameter

/ O [[:] sort_order]

controls the sort order of files in the displayed list. Without this parameter, file and directory names are listed in alphabetical order. By setting it appropriately, you can organize the output of files and directories in the reverse alphabetical order, in alphabetical order, or reverse order by extension names, in ascending or descending order of the date and time of the last modification of the contents of a file or directory, in ascending or descending order of their size.

A few more commands from the same group (names only):

MKDIR (MO) create a new directory;

CHDIR (CD) change to another directory.

File manipulation command; deletes files.

Syntax:

DEL [drive:] [path]

Parameter

[drive:] [path]

specifies the location and name of the file or filegroup to be deleted if wildcards are used in the name.

The / P switch prompts you for confirmation for each file you delete.

File manipulation command; copies one or more files to a specified location, and can also be used to merge files. Syntax:

COPY [+ source file [+ ...]] [result file]

The parameters consist of a drive designation, directory and file name.

specifies the location and name of the file whose content you want to copy.

specifies the location and name of the file into which to place the copied information.

/ Y indicates that the command should not ask for confirmation when replacing existing files;

/ V verifies that new files are written correctly.

Another team from the same group:

RENAME (REN) - rename a file or group of files;

Examples of system control commands are (only names are given):

COMMAND - start the command processor;

EXIT - exit from the command processor.

Additional utility commands

In addition to the commands recognized and executed by the command processor, the operating system has a large number of utilities - commands implemented in the form individual programs... As an example, consider the utility for formatting magnetic disks.

FORMAT - Formats a disk for use in MS DOS.

The FORMAT utility creates empty directories and FAT tables on the disk and checks for bad areas on the disk. It can destroy all data on the disk.

Syntax:

FORMAT disk:]

FORMAT disk:]

FORMAT disk:]

FORMAT disk:

Parameter

disk: indicates the disk to be formatted (this is the only required parameter of the utility).

/ V: label indicates the disk label, rarely used;

/ Q indicates that "quick" formatting is in progress; it is not necessary to check the damaged areas;

/ U indicates that there is no need to "restore" information before formatting;

/ F: size indicates the capacity of the floppy;

/ S copies the operating system files IO.SYS, MSDOS.SYS and COMMAND.COM to a floppy disk, which makes it bootable;

/ T: tracks indicates the number of tracks on the floppy disk;

/ N: Sectors Specifies the number of sectors on the floppy disk.

The command for working with disks (floppy); copies the contents of a floppy disk in one drive to a disk in another. Its syntax is as follows

DISKCOPY

Here are the first two objects in square brackets- parameters, the third is a key.

DISKCOPY A: B: copy the floppy disk in drive A to the diskette in drive B;

DISKCOPY A: copy the floppy disk in drive A to the diskette in the current drive;

DISKCOPY A: B: / I copy only the first side of the floppy disk.

A few more commands of the same group (only names; parameters and keys can be found in the references):

DISKCOMP - comparison of the contents of two floppy disks (in order to determine whether it is the same);

CHKDSK - checking the integrity of the file structure on the disk, correcting its errors;

RECOVER - restore (as far as possible) information on a defective disk.

A large number of MS DOS utilities are described in the manual for this system. Drivers are also important, especially for extended RAM, which are included with the operating system and allow more than 640 KB of memory to be used.

The files CONFIG.SYS and AUTOEXEC.BAT play a special role in the system; additional commands executed at system boot.

Executed before the shell is loaded and contains calls to the SYS drivers. Downloadable drivers are installed with the DEVICE command followed by the fully qualified filename of the driver file. For example, to connect the MOUSE.SYS mouse driver, you can use the command:

DEVICE = C: \ DOS \ MOUSE.SYS.

Starting with MS DOS 4.0, it is possible to load COM and EXE drivers using the INSTALL command. For example,

INSTALL = C: \ DOS \ MOUSE.COM.

To work effectively with different types computer microprocessors (80286, 80386, 80486, Pentium) and RAM sizes use special drivers:

DEVISE = C: \ DOS \ HIMEM.SYS

DEVISE = C: \ DOS \ EMM386.EXE NOEMS

DEVISE = C: \ DOS \ EMM486.EXE.

In addition to loading external drivers, CONFIG.SYS also loads its own (internal) commands.

If the computer does not have a hard disk cache (i.e., the buffer area of ​​RAM, where the contents of the disk blocks are stored), then the BUFFERS command is generated to speed up the work with the disk. A buffer is a 532 byte piece of RAM.

Using the FILES command, you can specify the number of files that can be simultaneously used by the system and programs.

The DOS command makes it possible to load operating system modules and some drivers into a memory area above 640 KB, thereby increasing the size of free base memory, which is important for a number of application programs.

Below are examples of typical configuration files:

1.for PC 286

REM Typical CONFIG.SYS

REM some drivers in HMA

REM (first 64 kbytes of memory area above 1 MB)

DEVICE = C: \ DOS \ HIMEM.SYS

DEVICE = C: \ WINDOWS \ MOUSE.SYS

DEVICE = C: \ STACKER \ STACHIGH.SYS

REM using data compression

2.for PC 386

REM Typical CONFIG.SYS

REM If possible, load operating system modules and

REM some drivers in NMA

REM (first 64 KB of memory area above 1 MB)

REM and UMB (blocks in the memory area between 640 KB and 1 MB)

REM Up to 20 files can be opened simultaneously

REM To work with files on the hard disk, use 5 buffers

DEVICE = C: \ DOS \ HIMEM.SYS

DEVICE = C: \ DOS \ EMM386.EXE NOEMS

REM with UMB support enabled

DEVICEHIGH = C: \ WINDOWS \ MOUSE.SYS

IBM PC- the first mass personal computer manufactured by IBM, released in 1981. In a broader sense, this is the name for the entire family of personal computers equipped with processors of the Intel x86 family.

IBM PC / XT computer (1984 execution)

IBM PC Model 5150

History

Until the 1980s, IBM was very active on large orders. Several times they were made by the government, several times by the military. She supplied her mainframes as a rule to educational and scientific institutions, as well as to large corporations. It is unlikely that anyone bought a separate System / 360 or 370 cabinet for themselves at home and a dozen of magnetic tape-based storage cabinets and already reduced a couple of times compared to the RAMAC 305 hard drives.

The blue giant was above the needs of the average consumer, who needs much less to be completely happy than NASA or another university. This gave a chance to stand on the feet of a semi-basement Apple company with the logo in the form of Newton holding an apple, soon replaced by a simply bitten apple. And Apple came up with absolutely simple thing- a computer for everyone. This idea was not supported by either Hewlett-Packard, where it was presented by Steve Wozniak, or other large IT companies of the time.

By the time IBM realized it, it was too late. The world has already admired the Apple II - the most popular and successful Apple computer in its entire history (not the Macintosh, as many believe). But it's better late than never. It was not difficult to guess that this market is at the very beginning of its development. The result was the IBM PC (Model 5150). It happened on August 12, 1981.

The most striking thing is that this was not the first personal IBM computer... The title of the first belongs to the 5100 model, released back in 1975. It was much more compact than mainframes, with a separate monitor, data storage and keyboard. But it was intended to solve scientific problems. For businessmen and just fans of technology, he was not suitable. And not least because of the price, which was around $ 20,000.

The IBM PC changed not only the world, but also the company's approach to building computers. Prior to that, IBM made any computer inside and out independently, without resorting to the help of third parties. It turned out differently with the IBM 5150. At that time, the personal computer market was split between the Commodore PET, the Atari family of 8-bit systems, the Apple II, and the Tandy Corporation's TRS-80s. Therefore, IBM was in a hurry to seize the moment.

A 12-person team based in Boca Raton, Florida, led by Don Estrige, was assigned to work on Project Chess. They completed the task in about a year. One of their key decisions was the use of third-party developments. This simultaneously saved a lot of money and time on our own scientific personnel.

Initially, Don chose the IBM 801 and a specially designed operating system for the processor. But a little earlier, the blue giant released the Datamaster microcomputer (full name System / 23 Datamaster or IBM 5322), which was based on the Intel 8085 processor (a slightly simplified modification of Intel 8088). This was the reason for the choice for the first IBM PC. Intel processor 8088. Even the expansion slots of the IBM PC were identical to those of the Datamaster. Well, Intel 8088 demanded a new DOS operating system, very timely proposed by a small company from Redmond called Microsoft. They did not make a new design for the monitor and printer. The monitor, previously created by the Japanese division of IBM, was chosen as the first, and the printer was made by Epson as a printing device.

The IBM PC was sold in various configurations. The most expensive one cost $ 3005. It was equipped with an Intel 8088 processor running at 4.77 MHz, which, if desired, could be supplemented with an Intel 8087 coprocessor, which made floating point calculations possible. The amount of RAM was 64 KB. As a device for permanent data storage, it was supposed to use 5.25-inch floppy drives. One or two of them could be installed. Later, IBM began to supply models that allowed the connection of cassette storage media.

The hard disk could not be installed in the IBM 5150 due to insufficient power supply. However, the company has a so-called "Expansion Unit" or Expansion Unit (also known as the IBM 5161 Expansion Chassis) with a 10 MB hard drive. He required a separate power source. In addition, a second HDD could be installed in it. It also had 5 expansion slots, while the computer itself had 8 more. But to connect the Expansion Unit, it was required to use the Extender Card and Receiver Card, which were installed in the module and in the case, respectively. The other expansion slots of the computer were usually occupied by a video card, cards with I / O ports, etc. It was also possible to increase the amount of RAM up to 256 KB.

The cheapest configuration cost $ 1,565. Together with it, the buyer received the same processor, but the RAM was only 16 KB. There was no floppy drive included with the computer, and there was no standard CGA monitor. But there was an adapter for cassette drives and a video card focused on connecting to a TV. Thus, an expensive modification of the IBM PC was created for business (where, by the way, it became quite widespread), and a cheaper modification was created for the home.

But there was another novelty in the IBM PC - the basic input / output system or BIOS (Basic Input / Output System). It is still used in modern computers today, albeit in a slightly modified form. Newest motherboards already contain newer EFI firmwares or even simplified ones Linux variants however, it will certainly be several years before the BIOS disappears.

The architecture of the IBM PC has been made open and publicly available. Any manufacturer could make peripherals and software for an IBM computer without purchasing any license. At the same time, the blue giant was selling the IBM PC Technical Reference Manual, where the complete source BIOS. As a result, a year later, the world saw the first "IBM PC compatible" computers from Columbia Data Products. Compaq and other companies followed.

Basic blocks of IBM

PC Typically, IBM PC personal computers consist of three parts (blocks):

· System unit;

· A keyboard that allows you to enter characters into a computer;

· Monitor (or display) - for displaying text and graphic information.

Computers are also produced in a portable version - in a "knee" (laptop) or "notebook" (laptop) version. Here the system unit, monitor and keyboard are enclosed in one case: the system unit is hidden under the keyboard, and the monitor is made as a cover for the keyboard. Although of these parts of the computer, the system unit looks the least impressive, it is he who is the "main" one in the computer. It contains all the main components of the computer:

· electronic circuits that control the operation of the computer (microprocessor, RAM, device controllers, etc.);

Power supply unit that converts the mains power supply into D.C. low voltage supplied to the electronic circuits of the computer;

Floppy disk drives (or drives) used to read and write to floppy disks magnetic disks(floppy disks);

· A hard disk drive designed for reading and writing to a non-removable hard magnetic disk (hard drive).

Additional devices

Various input-output devices can be connected to the system unit of an IBM PC, thereby expanding its functionality. Many devices are connected through special sockets (connectors), which are usually located on the back of the computer system unit. In addition to the monitor and keyboard, such devices are:

· Printer - for printing text and graphic information;

· Mouse - a device that facilitates the input of information into a computer;

· Joystick - a manipulator in the form of a handle with a button fixed on a hinge, used mainly for computer games;

· As well as other devices.

Some devices can be inserted inside the computer system unit, for example:

· Modem - to exchange information with other computers via the telephone network;

· Fax-modem - combines the capabilities of a modem and a telefax;

· Streamer — for storing data on magnetic tape. Some devices, for example, many types of scanners (devices for entering pictures and texts into a computer), use a mixed connection method: only an electronic board (controller) is inserted into the computer's system unit, which controls the operation of the device, and the device itself is connected to this board with a cable.

Configuration of the first IBM PC

Intel 8088 processor with a frequency of 4.77 MHz, RAM capacity from 16 to 256 KB.

Floppy drives with a capacity of 160 KB were purchased for an additional fee (one or two such drives could be connected).

Winchester was gone.

The key technologies are:

ISA system bus with standard slots, which made it possible to insert a variety of expansion cards (video, sound, network and other adapters) into the computer.

BIOS - set system functions, which allowed the software developer to abstract from the details of the operation of the hardware and not depend on the specific configuration of the system. (Until now, all software was developed only for specific machines and was supplied with them).

In the IBM PC, you could use either a monochrome MDA video adapter (text 80 × 25, character size 9 × 14), or a color video adapter CGA (text 80 × 25 or 40 × 25, character size 8 × 8, or graphics 320 × 200/4 colors or 640 × 200/2 colors). Moreover, you could even insert both adapters and connect two monitors at once, monochrome and color.

We all use personal computers and take them for granted in our Everyday life... It's easy enough to forget that computers have only been around us for the last few decades, and the first ones were much more massive than those on our desks today.

Did you know that the first laptop weighed 25 kg and cost about $ 20,000, that the first laser printer was so large that it filled most of the room, or that the first personal computer buyers had to assemble them themselves? This article will allow you to take a look at some of the first prototypes of computer hardware and see what they looked like.

The first computer mouse

The first computer mouse was invented in 1963 by Douglas Engelbart at the Stanford Research Institute. He is also one of the inventors of hypertext. The first mouse used two wheels at 90 degrees to each other to track movement along 2 axes. However, this design had many drawbacks, and soon the 2 wheels were replaced with a ball. The ball mouse was invented in 1972 and the optical mouse was invented around 1980, although this design became popular much later. Douglas Engelbart did not receive any royalties for his invention and his patent expired before computer mice became common in the era of personal computers.

First mouse. On the right, you can see the wheels that are used for movement and positioning.

First trackball

In fact, the trackball was designed 11 years before the invention of the first computer mouse... In 1952, it was invented by Tom Cranston and Fred Longstaff as part of the automated information warfare system DATAR, initiated by the Canadian Navy. The design used a 5-pin bowling ball, which is slightly smaller than a standard 10-pin bowling ball.

First trackball: bowling ball and that's it.

The first laptop

This computer was supposed to be a "mobile" computer. The IBM 5100 Portable Computer was created in 1975. It weighed 25 kg, was about the size of a small suitcase, and needed an external power source. The block contained everything needed: a processor, several hundred kilobytes of non-volatile memory, 16-64 KB of RAM, a 5-inch CRT display, a keyboard, and a tape drive. This computer was an incredible feat for the time. It also came with built-in BASIC and / or APL. Various models of the IBM 5100 cost from $ 8,975 to $ 19,975.

IBM 5100 Portable Computer.

First laptop

The first laptop was the Grid Compass 1100 (aka GRiD), designed in 1979 by British industrial designer Bill Moggridge. The computer went on sale in 1982. It was produced with a screen resolution of 320 x 200, an 8086 processor, 340 KB of magnet-electronic memory (this type of memory is now obsolete), a 1.2 Kbps modem. The laptop weighed 5 kg and cost $ 8,000 - 10,000. GRiD was mainly used by NASA and the US military.

Grid Compass 1100 close-up.

IBM's first personal computer

The first IBM personal computer entered service in 1981, it was the IBM 5150. The platform became so widespread in the 1980s that the term "personal computer" meant the IBM personal computer.

The IBM 5150 development project was called the Chess Project and was developed by a 12-person team led by Don Estridge and Larry Potter. To speed up development and reduce costs, IBM decided to use off-the-shelf parts rather than design new ones as it usually did.

The first IBM PC had an Intel 8088 processor, 64 KB of RAM (expandable up to 256 KB), a floppy drive (from which MS-DOS could be loaded) and finally a CGA or monochrome video adapter. The machine also contained Microsoft BASIC in ROM. The first IBM PC could optionally be installed HDD 10 MB, but only if the original power supply has been replaced with a more powerful one.

The first personal computer, the IBM PC 5160.

Apple's first computer

First personal Apple computers were designed and assembled by hand by Steve Wozniak. The Apple I went on sale in 1976 for $ 666.66. A total of 200 copies were produced. The Apple I basically had only motherboard with processor, 8K bytes of RAM, display interface and some additional functions... To get a fully working computer, the buyer must add a power supply, keyboard and display (and of course all this is mounted).

Computer Apple I. On the left is already assembled by the user, and on the right is the form in which you could buy.

First RAM

The first rewritable random access memory was magnetic core memory (also called ferrite memory). It was invented in 1951 as a result of work done by An Wang at the Computing Laboratory at Harvard University and by Jay Forrester at the Massachusetts Institute of Technology.

In those days, random access memory used the magnetic properties of materials to give them the functionality that transistors possessed. The information was stored using the polarity of the tiny magnetic ceramic rings through which the wires passed. Unlike modern memory, this random access memory could store information even after a power outage.

This technology was standard until it was replaced by silicon integrated circuits in the 1970s.

Magnetic core memory.

First hard drive

IBM 350 Disk File became the first hard disk, which was part of the IBM 305 RAMAC computer, the delivery of which began in 1956 (the computer was intended for accounting). The hard drive had fifty 24-inch drives that together could store 4.4 MB of data. The 350 had a rotation speed of 1200 rpm, a baud rate of 8,800 characters per second, and an access time of about 1 second.

IBM's first 350 Disk File hard drive.

The first laser printer

The laser printer was invented by Harry Starkweather at XEROX in 1969. The first prototype was a modified copier where he removed the imaging system and introduced a rotating drum with 8 mirrored edges. First commercial implementation laser printer did not occur until IBM released the IBM 3800 laser printer model in 1976. The printer was so large that it could take up most of the room.

IBM 3800, the first commercial laser printer.

First web server

Since the Internet is an integral part of the modern world, it is impossible not to talk about the first web server. The first web server was work station NeXT, which Tim Berners-Lee used when he invented the World Wide Web at CERN. The first web page became available online on August 6, 1991.

There was a sign on the computer that read: “This machine is a server. DO NOT TURN OFF!!". By turning it off, you could turn off the entire Internet.

The first web server and the famous inscription.

It's amazing how much has happened in the computer industry over the course of several decades. Now just imagine what will happen in 30-40 years ...

Translation of the article "The history of PC hardware, in pictures"

How Yandex uses your data and machine learning to personalize services -.

The world's first microprocessor appeared in 1971. It was the four-bit Intel 4004 microprocessor. Then, in 1973, the eight-bit Intel 8080 was released. On the basis of this processor, the very first microcomputers were created. These machines had very little capacity and were seen as simply amusing, but of little use, toys. In 1979, the first sixteen-bit microprocessors Intel 8086 and Intel 8088 were released. Based on the Intel 8086 in 1981, IBM released a personal computer IBM PC(PC -Personal Computer - personal computer), which in its capabilities has already approached the then existing mini-computers. Very quickly, these computers gained immense popularity all over the world due to their low cost and ease of use. A little later, a personal computer appeared IBM PC / XT(XT - extended Technology) with the maximum possible amount of RAM up to 1 MB. The next major step in the development of microprocessor technology was the release of personal computers in 1983. IBM PC / AT(AT - Advanced Technology - advanced technology) based on the Intel 80286 microprocessor with expanded up to 16 MB of the maximum possible amount of RAM. And by the end of the 80s, the 32-bit Intel 80386 was released with the maximum possible memory capacity of 4 GB. In the early nineties, a more powerful also thirty-two-bit Intel 80486 microprocessor appeared, which united more than a million transistor elements on one die. The Intel family continues to evolve, and in 1994 personal computers based on a microprocessor named Pentium, which in the course of development was marked as Intel 80586. Currently, several models with the Pentium brand are in use - Pentium II, Pentium MMX (with advanced multimedia capabilities), Pentium III and Pentium IV. Each subsequent model differs from the previous one by the expansion of the instruction set, the increasing clock frequency, the possible amount of RAM and hard disks, and an increase in overall efficiency. New, more advanced models are constantly being developed.

Computers of the IBM PC family were so successful that they began to be duplicated in almost all countries of the world. At the same time, computers turned out to be the same in terms of data encoding methods and command systems, but different in technical characteristics, appearance and cost. Such machines are called IBM-compatible personal computers. Programs written to run on an IBM PC can run just as well on IBM-compatible computers. In such cases, they say that software compatibility.

Other architectures

IBM PC family machines belong to the so-called CISC-architecture of computers (CISC - Complete Instruction Set Computer - a computer with a full set of instructions). In processor instruction systems based on this architecture, a separate instruction is provided for each possible action. For example, the processor instruction set Intel Pentium consists of over 1000 different teams. The wider the instruction set, the more memory bits are required to encode each individual instruction. If, for example, a command system consists of only four actions, then only two memory bits are required to encode them, three memory bits are required for eight possible actions, four for sixteen, etc. Thus, the expansion of the command system entails an increase the number of bytes allocated for one machine instruction, and, consequently, the amount of memory required to write the entire program as a whole. In addition, the average execution time of one machine instruction increases, and therefore the average execution time of the entire program.

In the mid-80s, the first processors with a reduced instruction system appeared, built according to the so-called RISC-architecture (RISC - Reduce Instruction Set Computer - a computer with a truncated instruction set). Instruction systems of processors with this architecture are much more compact, therefore programs consisting of instructions included in this system require significantly less memory and execute faster. However, for many complex actions, separate commands are not provided in such systems. When the need arises for such actions, they emulated through existing teams. Generally speaking, emulation is the execution of actions of one device using the means of another, carried out without loss functionality... V this case we are talking about performing the necessary complex actions for which the commands in the truncated system not provided, using a sequence of commands available in the system. Naturally, there is a certain loss of processor efficiency.

The RISC architecture includes fairly well-known machines of the company Apple Macintosh, which have a command system that in some cases provides them with more high productivity compared to machines of the IBM PC family. Another important difference between these machines is that many of the capabilities that are provided in the IBM PC family by purchasing, installing and configuring additional hardware are built-in in the Macintosh family and do not require any hardware configuration. True, Macintosh machines cost more than similar machines in the IBM family.

Machines of the families are often used as high-performance servers. Sun Microsystems, Hewlett Packard and Compaq which are also related to RISC architecture. As representatives of other architectures, we can also mention the families of portable computers of classes Notebook(portable) and Handheld(manual), which are small in size, light in weight and self-powered. These qualities make it possible to use the mentioned machines on business trips, at business meetings, scientific conferences etc., in a word, in cases where access to a stationary installed computers limited or not possible, such as on a train or plane.

Control questions

1. Give a definition to the concept of "computer architecture".

2. What are the three main groups of computer devices.

3. What is a number system and what number systems are used in personal computers to encode information?

4. What is the difference and what are the similarities between a bit and a byte?

5. How is it encoded in a PC text information?

6. How is it encoded in a PC graphic information?

7. Give definitions to the concepts "pixel", "raster", "resolution", "scanning".

8. What is the amount of memory, in what units is it measured?

9. What are the similarities and differences between operational and external memory?

10. Give definitions to the concepts of "loading" and "start" of the program.

11. Describe the floppy disk drives.

13. Describe the basic rules for handling floppy disks.

14. Give definitions to the concepts "work surface", "track", "sector", "cluster".

15. How to determine the size of the disk storage media?

16. What is the purpose of formatting magnetic disks?

17. Describe the hard disk drives.

18. Describe the drives on optical and magneto-optical disks.

19. Compare floppy disks, magnetic disks, optical disks, and magneto-optical disks.

20. How many disk devices can there be in personal computers? How are they designated?

21. Describe the main functions of the processor.

22. Give definitions to the concepts of "instruction system", "machine instruction", "machine program".

23. Indicate the main specifications processors.

24. What is a translator and what is it for?

25. What is a tire for? What is determined by its bit depth?

26. What is a motherboard?

27. What computer devices are in system unit?

28. Give the classification of displays and indicate their basic models.

29. What are adapters for?

30. What are the main modes of the keyboard.

30. What are the function keys for?

31. What is a keyboard shortcut?

32. What is a text cursor?

33. Explain how the text scrolls.

34. What is a screen text page?

35. Describe the main ways to move the text cursor.

36. What is a mouse for?

37. Specify the basic parameters and types of printers.

38. What is a scanner for? What other devices, similar in purpose, do you know?

39. What devices must be included in the computer in order for it to work in a multimedia environment?

40. What are modems for?

41. What is a family of computers?

42. What computers are considered software-compatible?

43. What are the basic models of the IBM PC family. How do they differ from each other?

The first full-fledged personal computer is considered to be the Apple II, released in June 1977. However, back in 1973, Xerox released the Xerox Alto personal computer, which had a THREE-BUTTON OPTICAL mouse! In addition, the computer's arsenal included Network Card and graphic user interface... This "luxury" for most users became available only after 10-17 years. The Xerox Alto itself never went on sale.

And in December 1974, the Altair 8800 became the first computer available at a price to everyone. This device was created on the basis of the new 8-bit Intel-8080 processor. CP / M was used as the operating system.

In 1975, Bill Gates and his colleague Paul Allen decided to write a BASIC interpreter for the Altair 8800 computer, and in one piece they founded the Micro-Soft company. The main specialization of the newly-minted company was the development of software for computers.

A year later, on April 1, 1976, Steve Jobs and Steve Wozniak founded Apple Computer, known for its "Apple Macintosh" series computers and other developments.

Due to the fact that personal computers became available to an increasing number of people, there has been growth in software development. As a result, a wide range of developed software has significantly accelerated the further distribution and use of PCs in society.

In the late seventies, the increase in demand for personal computers led to a decrease in demand for large and mini computers. The business world has realized that it is more profitable to buy computers than electronic computers. This turn of events caused serious concern in the IBM Corporation, which was at the time the leading computer company.

And so, in 1979, the bosses from IBM decided that as an experiment they should try their hand at the personal computer market. Meanwhile, about ten companies producing computers were already actively working on the PC market. In this regard, IBM decided not to waste time and large funds developing their own product from scratch.

One of the IBM departments responsible for this experiment was allowed to use parts made by other companies. And the developers decided to use the latest 16-bit Intel 8088 microprocessor as the main processor.

Remarkably what software was commissioned to develop a small firm called Microsoft, founded by Bill Gates 4 years before this event ...

Came August 1981 ... IBM officially presented to the public its new personal computer called the IBM PC. Users appreciated the new development and the IBM PC very quickly became very popular and after a couple of years the IBM PC became the standard for personal computers.

The reason for the tremendous success of the IBM PC is explained by the possibility of improving individual parts of the computer and using fundamentally new devices. Both then and now, you can assemble a computer from independently manufactured parts by analogy with a children's construction set.

Huge popularity The IBM PC contributed to the massive emergence of PC-compatible clones. The era of personal computers and the computer revolution has come.

In 1986, IBM could no longer maintain a leading position in the market for IBM PC-compatible computers, and in 2004 the company officially announced the sale of the production of personal computers. Lenovo, most large manufacturer computers in China ...