Binary Number System Basics

Power Supply

• Supplies power to the entire desktop computer system
• Plugs into an electrical outlet and receives power
• Converts alternating current (AC) to direct current (DC)
• Regulates current and smooths out voltage spikes to prevent damage to electronic components

Optical Drive (DVD/CD ROM)

• Uses a laser to read and write data on optical discs (DVD/CD)
• Reads data as zeros and ones from millions of small dips and bumps on the disc
• Can read and write data on discs, with the laser "burning" data onto the disc

Network Interface Card (NIC) or WiFi Card

• Connects a computer to a computer network (LAN)
• Allows for wired Ethernet or wireless WiFi connection
• Gives a computer its networking capabilities

Printers

Non-Impact Printers

• Do not use a striking device to produce characters on paper
• Quieter than impact printers
• Print a complete page at a time, also known as Page Printers
• Types of non-impact printers:

Inkjet Printers

• De-facto standard for consumer/home-use printers
• Inexpensive and use liquid ink that is relatively inexpensive to replace
• Can produce high-quality color printing or fast monochrome prints

Laser Printers

• Use a laser beam to heat a toner material that embeds itself onto the paper
• Most business-oriented models are monochrome, but there are color laser printers
• Toner cartridges are typically more expensive than ink, but last longer
• Faster print speed than inkjet printers, with higher print quality

Storage Measurements

• Basic unit of computer data storage is a bit (binary digit)
• Computers use bits to store and process data
• 1 byte = 8 bits
• Size examples:
  • 1 bit = answer to a yes/no question
  • 1 byte = a number from 0 to 255
  • 90 bytes = enough to store a typical line of text from a book
  • 4 KB = about one page of text
  • 120 KB = the text of a typical pocket book
  • 3 MB = a three-minute song (128k bitrate)
  • 650-900 MB = an CD-ROM
  • 1 GB = 114 minutes of uncompressed CD-quality audio at 1.4 Mbit/s
  • 8-16 GB = size of a normal flash drive

Memory

• Primary memory is an essential component of a computer system
• Program and data are loaded into primary memory before processing
• CPU interacts directly with primary memory to perform read or write operations
• Primary memory holds only those data and instructions on which the computer is currently working
• Has a limited capacity and data is lost when power is switched off
• Types of primary memory:

Random Access Memory (RAM)

• Volatile, meaning data is lost when power is switched off
• Used to store data temporarily while the computer is working
• Faster than secondary memory or storage devices
• Further classified into two types: SRAM (Static Random Access Memory) and DRAM (Dynamic Random Access Memory)

Read Only Memory (ROM)

• Not mentioned in the provided text