A microcomputer system

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Modern Microcomputer System

What is it?

A microcomputer system or commonly called a PC (Personal Computer) could be a desktop computer which name was given because of its size as it can fit on a desk, a laptop or a handheld PC. The PC has an operating system and many Software applications for personal use such as Microsoft Office, for word processing, database, spreadsheets ect. The PC could be used for games and special-purpose software such as CAD. Modern PC's have high-speed Ethernet or Wireless connections to allow access to the Internet and a wide range of other resources

A typical modern day computer would have the following components

  • Motherboard
  • CPU (Central Processing Unit)
  • Hard Drive
  • Graphics Card
  • Sound Card
  • RAM (Random Access Memory)
  • Case
  • PSU (Power Supply Unit)
  • DVD Drive

PC Hardware

The Motherboard

A motherboard on its own is lifeless, but a computer needs one work. The motherboard's main job is to hold the computer's CPU and let everything else connect to it. Everything that runs the computer increases its performance or usability is either part of the motherboard or plugs into it.

Parts of the motherboard

The Basic Input/output System (BIOS): This chip controls the most basic functions of the computer and performs a self-test every time you turn it on to make sure the pc is fully functional before the operating system boots up. Some systems feature dual BIOS, which provides a backup in case one fails.

  1. The Central Processing Unit Socket: This socket holds the CPU and determines what kind and type of CPU the motherboard can use e.g. AMD or Intel.
  2. The chipset: Is part of the motherboard's logic system. It is usually made of two parts, the Northbridge and the Southbridge. These two bridges connect the CPU to other parts of the computer so that it can function properly.
  3. The Real Time Clock Chip: This is a battery-operated chip that stores basic settings and the system time.
  4. Peripheral Component Interconnect (PCI): This slot provides connections for graphic cards, sound cards, network cards and many more peripherals.
  5. Peripheral Component Interconnect Express (PCI-E): this Slot has a newer protocol that allows the port to act more like a network rather than a bus. It has eliminated the need for other slots like the AGP port which is what older graphics card used. In modern day PC's many graphics cards are PCI-E because of the faster transfer rate.
  6. Memory slots: This slot holds the Random Access Memory (RAM) and connects it to the motherboard.

In most new motherboards rather than having plug-in cards, motherboards have on-board sound ports, network connections for Ethernet or even wireless, On board graphic support and other peripheral support. Also newer motherboards include Redundant Array of Independent Discs (RAID), this allows the computer to recognize multiple drives as one drive. There are many different types of RAID configurations, two of which can allow the user the back up his data on a separate hard drive, or use 2 hard drives as one.

CPU (Central Processing Unit)

What is the CPU?

The CPU is the brains of the computer, whether it is a Desktop PC or a Laptop. There are many different types of CPU, but they all do almost the same thing almost the same way. The first CPU was the Intel 4004, Made in 1971. The 4004 was not very powerful compared to the CPU's we use in today technology. All it could do was add and subtract which was done at 4 bits at a time which powered one of the first hand held calculators. Now day's we have 2 Main CPU Companies AMD and Intel which make 32bit and 64bit processors.

Current Trends

The trend in processor design has always been towards full 32-bit Arithmetic logic units (ALU). But the newest idea in processor design is toward 64-bit ALUs, and the addition of hardware virtual memory support and L1 caching on the processor chip. All of these trends push up the transistor count, leading to the multi-million transistor CPU's that are available today. These new processors can execute about one billion instructions per second.

64-bit CPU's

64-bit processors have been in home computers since 1992, Intel and AMD have introduced 64-bit processors which have 64-bit ALUs, 64-bit registers and 64-bit buses. With a 64-bit address bus and wide, high-speed data buses on the motherboard, 64-bit PC's offer faster I/O (input/output) speeds to peripherals like hard disk drives, graphics cards and sound cards. This can greatly increase system performance.

Current Processors

In modern day computers the main processors are either AMD or Intel. At the moment Intel have a rage of dual core and quad core processors.


Random Access Memory (RAM)

RAM provides space for your computer to read and write data to be accessed by the CPU. When you add more RAM to your computer, you reduce the number of times your CPU must read data from your hard disk as the RAM can store more data. This usually allows your computer to work considerably faster, as RAM has a very fast data access rate compared to the hard disk. RAM only stores data as long as your computer is running. As soon as you turn the computer off, the data stored in RAM is lost. When you turn your computer on, your computer's BIOS uses instructions stored semi-permanently in ROM chips to read your operating system and related files from the disk which is then loaded back into RAM.


There are several types of RAM that are used in modern computers. Before 2002 when DDR ram was released most computers used single data rate (SDR) RAM - Single Data Rate Random Access Memory. (SDR-RAM, SDR-SDRAM, Single Data Rate Synchronous -Dynamic Random Access Memory) RAM or SDRAM that transfers data on only one clock transition (0-1 or 1-0), in contrast to DDR-RAM.[1]

This meant the data access to the SDR-RAM was not very fast compared to the DDR-RAM as it only used one clock transition; this also affected the CPU's performance as it would slow it down because the data was not read as fast as it could have been. Most computers made since the (SDR) RAM then use either double data rate (DDR), DDR2, or DDR3 RAM.

DDR2 SDRAM is able to achieve faster transfer rates to prevent limitation of the CPU performance. DDR2 allows higher bus speed and requires lower power by running the internal clock at one quarter the speed of the data bus. DDR2 SDRAM gives a transfer rate of 3200 MB/s

DDR3 SDRAM is an improvement over DDR2 SDRAM, but the two are not compatible. The benefit of having DDR3 is the ability to send and receive data at twice the data rate of DDR2 therefore enabling higher bus rates than earlier RAMs like DDR. DDR3 standard allow a maximum module size of 16 gigabytes, DDR3 SDRAM gives a maximum transfer rate of 6400 MB/s.

All of these different types of RAM are not interchangeable. Only one type of RAM will function with each other, if installed with another type, physical difference stop the modules being slotted in to the Memory slots to avoid Error's.

Graphics Card

­The Graphics card connects to the computer through the motherboard via a Port. The motherboard supplies power to the card and lets it communicate with the CPU, sometimes newer graphics cards often require more power than the motherboard can provide because of the size of the GPU, RAM and sometimes additional fan to cool down the card while it operates. So they also have a direct connection to the computer's power supply unit PSU. Connections to the motherboard are usually through one of three interfaces in these modern technologies:

  1. Peripheral component interconnect (PCI)
  2. Advanced graphics port (AGP)
  3. PCI Express (PCI-E)

PCI Express is the newest of the three and provides the fastest transfer rates between the graphics card and the motherboard. PCI-E also supports the use of two graphics cards in the same computer which has a great advantage over the AGP and PCI as the PC can have twice the graphical power which would be handy for game designers and media editors. ­Most graphics cards have two monitor connections. In most modern graphic cards one is a DVI connector and the other is a VGA connector. This can be used for connecting two screens on the same PC this allows the user to have multi screen pc use where the desktop spreads of two screens.

Hard Drive

A hard drive is a device that stores data on a disk which is not wiped when the pc is turned off. The disk rapidy rotates platters with magnetic surfaces. Early hard drives had removable media, e.g magnetic tapes. But todays hard drives are a sinlge unit which stays within the pc case.The hard drive it conncted to the motherboard, over the years the type of connection has changed from the widley used Parallel ATA (PATA)which also connected the CD drives and solid state drives to the motherboard. But now modern day hard drives are connected by Serial ATA