Computer Hardware

Lally School of M&T- Microcomputing and Info Systems Lecture Topics 1. Data Representation 2. Data Metrics 3. Central processing Unit 4. Primary storage 5. Secondary storage

Lally School of M&T- Microcomputing and Info Systems Data Representation Computers understand 0s and 1s. Computers use electrical current 0 is off, 1 is on. Digital format of data. Bit = 0 or 1 A series of 8 bits represents a character 1 Byte = 8 bits Mary consists of four combinations of 8 bits or 4 bytes

Lally School of M&T- Microcomputing and Info Systems Data Representation ASCII (American Standard Code for Information Interchange) requires only 7 bits for each character. 128 characters are defined. Extended ASCII uses eight bits for each character 256 possible characters are defined. Unicode uses 16 bits and provides codes for around 65,000 characters – a bonus for representing alphabets of multiple languages.

Lally School of M&T- Microcomputing and Info Systems Data Metrics Kilo means a 1000 Mega means million Giga means billion Tera means trillion

Lally School of M&T- Microcomputing and Info Systems The Motherboard

Lally School of M&T- Microcomputing and Info Systems Expansion Slots Properties PCI (Peripheral Component Interconnect) - for graphics, sound, video, modem or network cards. The most common expansion slot as of today. AGP (Accelerated Graphics Port) - made specifically for graphics cards. PCI Express - Very modern expansion slot. Very fast communication between the circuitry and the processor. Expansion cards are built for only one type of slot.

Lally School of M&T- Microcomputing and Info Systems Expansion Slots

Lally School of M&T- Microcomputing and Info Systems Expansion Cards

Lally School of M&T- Microcomputing and Info Systems CPU Chip

Lally School of M&T- Microcomputing and Info Systems CPU Socket

Lally School of M&T- Microcomputing and Info Systems CPU Characteristics Control Unit Hardware/Software control Coordinates and controls the components of the computer. Processes programs and directs other devices to perform what the program asks. It reads programs one instruction at a time and the processing time is the machine cycle of the computer. Arithmetic Logic Unit Performs the requested logical and arithmetic operations. Not all machines are equipped with ALUs

Lally School of M&T- Microcomputing and Info Systems RAM Characteristics RAM It is called RAM or Random Access Memory. Its purpose is to store part or whole of the application program that is being executed. Also, it stores OS programs necessary for the operation of the computer. Furthermore, it stores the data that the operating system or application program is using. The content of RAM is erased once the computer is turned off. ROM It stands for Read Only Memory. It can only be read. We cannot write on it. Its contents are not erased once the computer is turned off. It contains mainly firmware instructions, that is, what kind of hardware we have. Today this type of memory is being replaced by flash memory that can be written and updated as needed.

Lally School of M&T- Microcomputing and Info Systems RAM Chips

Lally School of M&T- Microcomputing and Info Systems RAM Slots

Lally School of M&T- Microcomputing and Info Systems Hard Disk – Secondary Storage

Lally School of M&T- Microcomputing and Info Systems Hard Disk – Magnetic Disk

Lally School of M&T- Microcomputing and Info Systems Hard Disk Characteristics Data Rate: The rate at which the disk can deliver data to the CPU Seek Time: The lapse of time between a CPU request of data and delivery of first byte Capacity: The number of GBs of data it can store. Rotational Speed: The rate at which the HD platters spin usually between 3,600 to 10,000 rpm Cache (Desirable if existing) Interfaces: ATA (IDE, EIDE.) SCSI, USB (Advanced Technology Attachment, Small Computer System Interface, Universal Serial Bus)

Lally School of M&T- Microcomputing and Info Systems 19 Solid State Storage Solid state storage technology stores data in an erasable, rewritable circuitry. Non-volatile Much faster More reliable

Lally School of M&T- Microcomputing and Info Systems CDROM and CD-DRIVE

Lally School of M&T- Microcomputing and Info Systems CDROMs: Secondary Storage