Usman Ghani 90420305686 PRACTICAL: 1 INTRODUCTION TO COMPUTER HARDWARE COMPUTER HARDWARE : Hardware is the term used to describe the tangible parts of your computer system. This includes all of the devices, both internal and external, that connect to your computer so that it can perform all sorts of operations. Central Processing Unit (CPU) The Central Processing Unit (CPU), also called a microprocessor, or simply a processor. It is located on the motherboard and is an integrated circuit that contains millions and millions of transistors and other electrical components. 1 Usman Ghani 90420305686 Functions of the CPU: CPU performs a series of computations to carry out tasks. The Arithmetic/Logic Unit (ALU) is the part of the central processing unit that performs various calculations and comparisons. Some basic operations like addition, subtraction, multiplication, and division. Whenever the CPU wants to access a certain piece of data, the address bus will send the address to the memory, and the data bus, will receive the data from the memory. Another of the CPU's basic functions is that it can make certain decisions about how the computer is operated, and based on these decisions, the CPU can jump from one instruction to another. The CPU also has a pipelining technology that allows it to perform many different instructions simultaneously. Parts of the CPU : 1. Control Unit (CU): 2 Usman Ghani 90420305686 The control unit supervises all of the CPU's operations. It fetches the software instructions from the memory, and it also coordinates the times and order in which the instructions are carried out. 2. Arithmetic/Logic Unit (ALU): The arithmetic/logic unit is the part of the CPU that does the actual computing. Data is brought here, where it is operated on. The ALU can perform both arithmetic and logical operations. 3. Registers: Registers are special storage locations located inside the CPU. The data contained here can be accessed much quicker than the data contained in other memory locations, such as the RAM (random-access memory) and the ROM (read-only memory). Registers in different parts of the CPU are used for different functions. 4. Memory: Memories are one of the most important parts of a computer system. The term memory refers to any device that can be used for storage. There are two basic ways to store memory. One way is to store the memory within the actual circuitry of the computer, which allows for it to be quickly accessed by the central processing unit. These memory devices are generally used for temporary storage of data and programs that are currently used by the CPU. The second type of memory storage is to store the memory in external storage devices. They include hard drives , floppy disks, and CD-ROMs. Types of Memories: 1. Random-Access Memory Random-access memory, or RAM,is a temporary storage place where your computer holds files and data that you are using at the present moment. 2. Read-Only Memory 3 Usman Ghani 90420305686 Read- only memory, or ROM, stores permanent information. The data stored here can not be altered or changed in any way 3. Caches: Caches are extremely fast, temporary memories. Sometimes, they are even located right within the CPU for extra-quick data retrieval! 4. Virtual Memory: Virtual memory is a special memory that lets your computer handle many programs and applications with only a small amount of RAM 4 Usman Ghani 90420305686 Motherboard: The motherboard is a very integral part of your computer system. The motherboard contains a complex array of circuits, chips, and wires. It is here that the most vital part of your computer system are located. Located on the motherboard are the: 1. Central Processing Unit (CPU) 2. Memory 3. System BIOs 4. System Bus Motherboards come in different sizes and shapes. Form factor is a term that relates to the physical shape and size of a motherboard. Two motherboards can have essentially the same components, but these parts can be arranged differently. Thus, the two motherboards would have different form factors. This section describes some of the more popular motherboard form factors. AT/Baby AT TX/Mini ATX LPX/Mini LPX NLX DIFFERENT STORAGE DEVICES: 5 Usman Ghani 90420305686 1. Magnetic Disk: A magnetic disk's medium contains iron particles, which can be polarized—given a magnetic charge-in one of two directions.Each particle's direction represents a 1 (on) or 0 (off), representing each bit of data that the CPU can recognize. A disk drive uses read/write heads containing electromagnets to create magnetic charges on the medium. 2. Hard disk: Data is stored by magnetising the surface of flat, circular plates called platters which have a surface that can be magnetized. They constantly rotate at very high speed. A read/write head floats on a cushion of air a fraction of a millimeter above the surface of the disc. The drive is inside a sealed unit because even a speck of dust could cause the heads to crash 3. Floppy disk: In 1969 the first floppy disk was introduced. It was a read only 8 inch disk that could store 80kB of data. 4 years later, in 1973, the a similar floppy disk with the same size could store 256kB of data plus it was possible to write new data again and again. Since then the trend has been the same smaller floppy disks that could store more data. In the late 1990s you could get ahold of 3 inch disks that could store 250 MB of data. These can be found on most microcomputers and accept the usual 3.5 inch floppy discs. High density discs for a PC hold 1.44 MB of data (enough to store about 350 pages of A4 text). A floppy disc needs to be formatted before it can be used but most discs are now sold already formatted for PC's. 4. Magnetic Tape: Magnetic tape is a medium for magnetic recording generally consisting of a thin magnetizable coating on a long and narrow strip of plastic. Nearly all recording tape is of this type, whether used for recording audio or video or for computer storage. 5. CD -Rom: CD-ROM - means Compact Disc - Read Only Memory. This means you can only read from the disc, not write or store data onto it. They are also known as optical discs because the data is read by a laser beam reflecting or not reflecting from the disc surface. Like a floppy disc, a CD-ROM only starts spinning when requested and it has to spin up to the correct speed each time it is accessed. It is much faster to access than a floppy but it is currently slower than a hard disc. 6 Usman Ghani 90420305686 6. Photo CD: Photo CD is a system designed by Kodak digitizing and storing photos in a CD. Launched in 1992 the discs were designed to hold nearly 100 high quality images, scanned prints and slides using special proprietary encoding. Photo CD discs are defined in the Beige Book and conform to the CD-ROM XA and CD-i Bridge specifications as well. They are intended to play on CD-i players, Photo CD players and any computer with the suitable software irrespective of the operating system The images can also be printed out on photographic paper with a special Kodak machine 7. USB Flash drive: A USB flash drive consists of a NAND-type flash memory data storage device integrated with a USB (universal serial bus) interface. USB flash drives are typically removable and rewritable, much smaller than a floppy disk (1 to 4 inches or 2.5 to 10 cm), and most USB flash drives weigh less than an ounce. Storage capacities typically range from 64 MB to 64 GB with steady improvements in size and price per gigabyte. Some allow 1 million write or erase cycles and have 10-year data retention, connected by USB 1.1 or USB 2.0 Input /Output Devices Input/output devices are the devices that connect you to your computer. Input devices let you input data and other information into your computer and they also let you give your computer special instructions so that it will know what to do. For example, you can type in data by using a 7 Usman Ghani 90420305686 keyboard, or you can input data in picture form by using a scanner. On the other hand, output devices display the results of your computer's computations. Examples of these would be your computer's monitor, which displays all of the programs you're running, as well as the printer, which will print out a hard copy of the information! Input Devices: 1. Keyboard: I'm sure that you all know what a keyboard is. A keyboard is what you use to type in letters, numbers, and other characters. You can type instructions in to your computer, or you can use the keyboard to type up documents. 2. Mouse: Mouse have been around for some while now. Mouse are used to manuever the cursor on your computer screen to give instructions to your computer and to run programs and applications. 3. Scanner: Scanners let you put pictures and images onto your computer. They convert pictures and iamges to digital form so that you can edit them by using the computer or put them on the Internet! 8 Usman Ghani 90420305686 4. Digital Camera: Digital cameras are somewhat similar to regular cameras. You can take pictures of people, places, or things. However, digital cameras convert these pictures to digital form so they can be used on the computer.