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
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 MetricsKilo 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 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.
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
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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 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)
Lally School of M&T- Microcomputing and Info Systems
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Solid State StorageSolid state storage technology stores data in
an erasable, rewritable circuitry.Non-volatileMuch fasterMore reliable
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CDROM and CD-DRIVE
Lally School of M&T- Microcomputing and Info Systems
CDROMs: Secondary Storage