computer hardware. lally school of m&t- microcomputing and info systems lecture topics 1. data...

Computer Hardware

Lally School of M&T- Microcomputing and Info Systems

Lecture Topics

1. Data Representation2. Data Metrics3. Central processing Unit4. Primary storage5. Secondary storage


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


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.


Data MetricsKilo means a 1000 Mega means million Giga means billion Tera means trillion


The Motherboard


Expansion Slots PropertiesPCI (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.


Expansion Slots


Expansion Cards


CPU Chip


CPU Socket


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


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.


RAM Chips


RAM Slots


Hard Disk – Secondary Storage


Hard Disk – Magnetic Disk


Hard Disk CharacteristicsData Rate: The rate at which the disk can

deliver data to the CPUSeek Time: The lapse of time between a CPU

request of data and delivery of first byteCapacity: 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)


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Solid State StorageSolid state storage technology stores data in

an erasable, rewritable circuitry.Non-volatileMuch fasterMore reliable


CDROM and CD-DRIVE


CDROMs: Secondary Storage

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