Computer Architecture

Bits and Pieces

1. The term Bit refers to a binary digit, that is the smallest unit of data in a computer,

comprising of a single binary value.

The term Byte refers to a unit of data that is eight binary digits long. Bytes are units

used by most computers in representing characters.

A Kilobyte refers to approximately a 1024 bytes, as a measure of computer

storage or memory.

A Megabyte refers to approximately a million bytes, thereby being a 1024

kilobytes, as a measure of computer storage and real or virtual memory.

A Gigabyte refers to approximately a billion bytes, and is a measure of

capacity of computer data storage.

2. The term Millisecond refers to one thousandth of a second and is frequently used in

measuring time to read to or write from a hard disk or CD-ROM player.

The term Nanosecond refers to one billionth of a second and is frequently used in

measuring read or write access time to RAM (Random Access Memory).

3. To store 256 different values, 8 bits are required.

4. In the memory of a computer video card with a capacity of 32 megabytes, 32 768

kilobytes or 33 554 432 bytes or 268 435 456 bits can be stored.

Input / Output Devices

1. The term Input Device refers to any harware device through which data as well as

instructions are entered in to the computer's main memory. Incoming data is converted

into electrical impulses, that are sent to other units of the computer.

The term Output Device refers to any device used to take information out of a

computer.

2. Computer Controlled Lathe ( Output Device

Light Sensor in a Digital Camera ( Input Device

Robot Welder ( Output Device

Temperature Sensor in a Computer Controlled Blast Furnace ( Input Device

3. A modem is considered to be both an input and an output device as it is a

communications device that receives input from a phone line, or a cable, and gives it to

the processor. Then, output from the processor is sent to the phone line or cable.

4. Serial Transmission is where data is sent one bit at a time while Parallel

Transmission is a method of transmission where multiple bits (usually eight) are

simultaneously sent. These forms of transmissions generally occur within

communications devices.

5. Two common serial devices would be a Serial Printer and a Modem, while two parallel

devices would be a Parallel Scanner and Zip Drive.

6. The term USB refers to the Universal Serial Bus, a standard port that enables you to

connect external devices, peripherals, computers.

USB devices are now common as the connection is quick and easy and the device

supports a large number of devices per interface. The technology, that has recently

come about, seems to have distinct advantages over the original serial interface.

7. Device drivers, in simple terms, are pieces of software code that tell the operating

system on how to use hardware correctly. As every manufacturer has different

hardware devices, manufacturers make device drivers for each device. Thus, device

drivers are needed to utilize devices including printers and scanners as their