Untitled Quiz

Computer Organization vs Computer Architecture

• Computer Organization refers to the physical attributes and structure of hardware such as circuit design, memory types, and control signals.
• Computer Architecture focuses on the logical attributes visible to the programmer such as instruction sets, data types, addressing modes, and instruction formats.
• There's a gray area between organization and architecture due to the Principle of Equivalence of Hardware and Software. This principle states that anything done with hardware can be done with software, and vice versa.

Fundamental Components of a Computer

• Computers are devices consisting of four essential components: input, processing, output, and storage.
• Input: Accepts information from the outside world.
• Processing: Interprets and executes programs to manipulate information.
• Output: Returns processed information to the outside world.
• Storage: A memory for short-term or long-term storage of information or data, and program instructions.

Units of Measure in Computer Systems

• Capacity in computers is measured using prefixes derived from Greek:
  • Kilo- (K): 1 thousand = 103 and 210 (approximately 1 thousand)
  • Mega- (M): 1 million = 106 and 220 (approximately 1 million)
  • Giga- (G): 1 billion = 109 and 230 (approximately 1 billion)
  • Tera- (T): 1 trillion = 1012 and 240 (approximately 1 trillion)
  • Peta- (P): 1 quadrillion = 1015 and 250 (approximately 1 quadrillion)
  • Exa- (E): 1 quintillion = 1018 and 260 (approximately 1 quintillion)
  • Zetta- (Z): 1 sextillion = 1021 and 270 (approximately 1 sextillion)
  • Yotta- (Y): 1 septillion = 1024 and 280 (approximately 1 septillion)
• Speed is measured in Hertz (Hz), which represents cycles per second:
  • 1MHz = 1,000,000Hz
  • Processor speeds are measured in MHz or GHz.
• Byte is the basic unit of storage:
  • 1 KB = 210 = 1024 Bytes
  • 1 MB = 220 = 1,048,576 Bytes
  • 1 GB = 230 = 1,099,511,627,776 Bytes
  • Main memory (RAM) is measured in GB.
  • Disk storage is measured in GB for smaller systems, and TB for larger systems.
• Time and Space are measured using decimal-based prefixes:
  • Milli- (m): 1 thousandth = 10-3
  • Micro- (µ): 1 millionth = 10-6
  • Nano- (n): 1 billionth = 10-9
  • Pico- (p): 1 trillionth = 10-12
  • Femto- (f): 1 quadrillionth = 10-15
  • Atto- (a): 1 quintillionth = 10-18
  • Zepto- (z): 1 sextillionth = 10-21
  • Yocto- (y): 1 septillionth = 10-24

Time and Space Examples in Computer Systems

• Hard disk drive access times are measured in milliseconds.
• RAM access times are much faster, measured in nanoseconds.
• Older circuit distances were measured in microns, but modern technologies use nanometer-scale measurements.

Byte, Character Sets, and Data Storage

• A byte is an 8-bit quantity.
• One byte can represent 28 (256) values, from 0 to 255, which is enough for standard North American and Western European character sets.
• Representing characters in languages like Chinese, Japanese, Hindi, and Arabic requires more bits, using a 2-byte (16-bit) system called Unicode.
• A typical typed page of text, without formatting, is around 2K of data.
• Cache and RAM are measured in MB and GB.
• Disk and solid state storage are measured in GB and TB.

Speed, Cycle Time, and Clock Frequency

• Speed is measured in Hertz (Hz), which represent cycles per second.
• Cycle time is the reciprocal of the clock frequency.
• For example, a bus with a 133MHz operating frequency has a cycle time of:
  • Cycle time = 1/frequency = 1/133MHz = 7.517ns

RAM, Cache, and Storage Performance

• RAM (Random Access Memory) allows direct access to any part of its contents, if the location (address) is known.
• Cache is a special type of super-fast RAM that can be accessed much faster than regular RAM. It is located within the processor and holds instructions about to be processed or those repeatedly used in loops.
• Larger RAM capacity is necessary to run modern programs, which tend to be quite large.
• If a computer lacks sufficient RAM, the hard disk is used to simulate RAM, which is significantly slower.
• Hard disk access speed is about 1000 times slower than RAM access speed.
• Therefore, a computer without enough RAM will be slow.

Data Transfer Methods

• Serial ports transmit data as a series of pulses along one or two data lines.
• Parallel ports send data as a single pulse along at least eight data lines.
• USB (Universal Serial Bus) is an intelligent serial interface that self-configures.