So, what does our ordinary personal computer (PC) consist of, which we use at home or at work.
Consider its hardware ("hardware"):
- system unit (that big box that is on your desk or under the desk, on the side of it, etc.). It contains all the main computer nodes.
- peripheral devices (such as a monitor, keyboard, mouse, modem, scanner, etc.).
The system unit in the computer is the “main” one. If you carefully unscrew the screws from its back wall, remove the side panel and look inside, then only with the appearance of its device will seem complicated. Now I will briefly describe his device, and then I will describe the main elements in the most understandable language.
The following elements are placed in the system unit (not necessarily all at once):
- mathematical coprocessor;
- clock generator;
- memory chips (RAM, ROM, cache, CMOS memory)
- controllers (adapters) of devices: keyboards, disks, etc.
- sound, video and network cards;
- timer, etc.
All of them are connected to the motherboard using connectors (slots). Its elements in bold will be discussed below.
And now, in order about the system unit:
1. Everything is clear with the power supply: it powers the computer. I can only say that the higher its power indicator, the steeper.
2. The hard disk drive (HDD. hard disk drive) in common people is called the hard drive.
This nickname arose from the slang name of the first 16 Kbyte hard drive model (IBM, 1973), which had 30 tracks of 30 sectors each, which accidentally coincided with the “30/30” caliber of the famous Winchester hunting rifle. The capacity of this drive is usually measured in gigabytes: from 20 GB (on older computers) to several Terrabytes (1TB = 1024 GB). The most common hard drive capacity. 250-500 GB. The speed of operations depends on the speed (5400-10000 rpm). Depending on the type of connection between the hard drive and the motherboard, ATA and IDE are distinguished.
3. A floppy disk drive (FDD) is nothing more than a floppy disk drive. Their standard capacity is 1.44 MB with a diameter of 3.5" (89 mm). As a storage medium for magnetic disks, magnetic materials with special properties are used that allow fixing two magnetic states, each of which is assigned binary numbers: 0 and 1.
4. Optical disc drives (CD-ROM) come in different diameters (3.5" and 5.25") and containers. The most common of them. with a capacity of 700 MB. It happens that CD discs can be used for recording only 1 time (then they are called R), but it is more profitable to use rewritable RW discs.
DVD was originally decoded as Digital Video Disk. Despite the name, you can burn anything you want on DVDs. from music to data. Therefore, recently, another decoding of this name — Digital Versatile Disk — in free translation meaning “digital universal disk”, has been increasingly found. The main difference between DVDs and CDs is the amount of information that can be recorded on such media. From 4.7 to 13, and even up to 17 Gb, can be recorded on a DVD. This is achieved in several ways. Firstly, a laser with a shorter wavelength is used to read DVDs than to read CDs, which significantly increased the recording density. Secondly, the standard provides for the so-called double-layer discs, on which data is recorded in two layers on one side, with one layer translucent, and the second layer read through the first. This allowed us to record data on both sides of DVDs, and thus double their capacity, which is sometimes done.
5. Other additional devices (mouse, printer, scanner, etc.) can be connected to a personal computer. Connection is made through ports. special connectors on the rear panel.
Ports are parallel (LPT), serial (COM) and universal serial (USB). The serial port transmits information bitwise (more slowly) over a small number of wires. A mouse and a modem are connected to the serial port. On a parallel port, information is transmitted simultaneously over a large number of wires corresponding to the number of bits. A printer and an external hard drive are connected to the parallel port. A USB port is used to connect a wide range of peripherals. from a mouse to a printer. It is also possible to exchange data between computers.
6. The main computer devices (processor, RAM, etc.) are located on the motherboard.
A microprocessor (easier. Processor) is the central unit of a PC designed to control the operation of all units of the machine and to perform arithmetic and logical operations on information.
Its main characteristics are bit depth (the higher it is, the higher the performance of the computer) and the clock frequency (largely determines the speed of the computer). The clock frequency indicates how many elementary operations (clocks) the processor performs in one second.
Intel Pentium processors and its economy version of Celeron are respected in the market, as well as their competitors. AMD Athlon with the Duron economy version. Intel processors are characterized by high reliability, low heat and compatibility with all software and hardware. And AMD show greater speed with graphics and games, but less reliable.
Computer memory is internal and external. External memory devices include the already discussed HDD, FDD, CD-ROM, DVD-ROM. Internal memory includes a permanent memory (ROM, ROM English), operational memory (RAM, RAM English), cache.
ROM is intended for storing constant program and reference information (BIOS. Basic Input-Output System. basic input-output system).
RAM has a high speed and is used by the processor for short-term storage of information during computer operation.
When the power source is turned off, information is not saved in RAM. For the normal functioning of the computer these days it is advisable to have from 1 GB to 3 GB of RAM.
Cache memory is an operational superfast intermediate memory.
CMOS memory. CMOS RAM (Complementary Metall-Oxide Semiconductor RAM). It stores computer configuration parameters, which are checked every time the system is turned on. To change the computer configuration parameters in the BIOS contains the computer configuration program. SETUP.
Sound, video and network cards can be either built-in to the motherboard or external. External boards can always be replaced, whereas if the integrated video card fails, you will have to change the entire motherboard. Of the video cards, I trust ATI Radeon and Nvidia. The higher the memory capacity of the video card, the better.
The computer keyboard consists of 6 groups of keys:
- Controls (Enter, Backspace, Ctrl, Alt, Shift, Tab, Esc, Caps Lock, Num Lock, Scroll Lock, Pause, Print Screen);
- Functional (F1-F12);
- Numeric keypad;
- Cursor control (->, <-, Page Up, Page Down, Home, End, Delete, Insert);
- Function indicator lights (Caps Lock, Num Lock, Scroll Lock).
Mouse (mechanical, optical). Most programs use two of the three mouse buttons. The left key is the main one, it is controlled by a computer. It plays the role of the Enter key. The functions of the right key depend on the program. In the middle is the scroll wheel, which you quickly get used to.
The modem is a network adapter. It can be both external and internal.
The scanner automatically reads from paper and enters any printed texts and images into the PC.
The microphone is used to input sound into the computer.
The monitor (display) is designed to display information on the screen. Most often, modern PCs use SVGA monitors with a resolution (the number of dots located horizontally and vertically on the monitor screen) 800600, 1024768, 12801024, 16001200 with up to 16.8 million colors.
The monitor screen size is from 15 to 22 inches diagonally, but most often. 17 inches (35.5 cm). The size of the point (grain) is from 0.32 mm to 0.21 mm. The smaller it is, the better.
PCs that are equipped with television monitors (CRTs) are no longer as popular. Of these, monitors with low radiation (Low Radiation) should be preferred. Liquid crystal displays (LCDs) are more secure, and most computers have just such a monitor.
The printer is designed to print text and graphics. Printers are matrix, inkjet and laser. In dot-matrix printers, the image is formed from dots by the impact method. Instead of needles, inkjet printers in the print head have thin tubes — nozzles through which tiny droplets of ink are thrown onto the paper. Inkjet printers also perform color printing by mixing basic colors. The advantage is high print quality, the disadvantage is the danger of ink drying, the high cost of consumables.
Laser printers use an electrographic imaging method. The laser is used to create an ultra-thin light beam, drawing on the surface of a pre-charged photosensitive drum the contours of an invisible point electron image. After the development of the electronic image by the dye (toner) powder adhering to the discharged areas, printing is performed — the toner is transferred from the drum to the paper and the image is fixed on the paper by heating the toner until it is melted. Laser printers provide the highest quality, fastest printing. Widely used color laser printers.
Speakers output sound. The sound quality depends. again. on the power of the speakers and the material from which the body (preferably wood) is made and its volume. An important role is played by the presence of a bass reflex (a hole on the front panel) and the number of bands of reproduced frequencies (high, medium and low speakers on each speaker).
USB flash drives, in my opinion, have become the most versatile means of transferring information. This miniature device is smaller and lighter in size and weight. It has high mechanical strength, is not afraid of electromagnetic radiation, heat and cold, dust and dirt.
The most sensitive part of the drive is the connector covered with a cap. The volume of these devices ranges from 256 MB to 32 GB, which allows you to choose the drive of the desired capacity, in accordance with the needs. Thanks to the interface, the USB drive can be connected to any modern computer. It works with operating systems Windows 98SE / Me / 2000 / XP / Vista / 7, Mac OS 8.6
10.1, Linux 2.4. In Windows, you don’t even need to install any drivers: plugged into a USB port. and go.
A webcam is needed to enter a dynamic image into a computer and sound (for communication and the possibility of creating teleconferences).
An uninterruptible power supply is needed in case of emergency power outages.
Fuff, well, in my opinion, and all the main things that I wanted to tell you about the hardware of the computer, the so-called hardware.
The article “Computer device” was written a long time ago. Therefore, if you find a mistake or find some inaccuracy, please write about it using the comment form. We will be very grateful to you!