- Impact printer
- Print head strikes inked ribbon
- Line printers
- Band printers
- Speed measured in characters per second
Thursday, December 25, 2008
- Non-impact printer
- Inexpensive home printer
- Color output common using CMYK
- Cyan, magenta, yellow, black
- Sprays ink onto paper
- Speed measured in pages per minute
- Quality expressed as dots per
– Non-impact printer
– Produces high quality documents
– Color or black and white
– Print process
• Laser draws text on page
• Toner sticks to text
• Toner melted to page
– Speed measured in pages per minute
– Quality expressed as dots per inch
Definition of memory and its
• When you launch a program, it is loaded into and run from memory
Ø Classification of Memory
Ø Internal Processor Memory
Ø Main Memory:
Ø Secondary Memory:
Example: CD, Floppy etc.
ü Byte: 1 byte= 8 bits
ü Kilobyte (K or KB): 1KB=1024 bytes
ü Megabyte (M or MB): 1MB=1048579 bytes
ü Gigabyte (G or GB): 1GB=1048876 byte
General Properties of Memory Devices
• Access Time: The average time required to read a fixed amount of information from the memory
• Cycle time: The minimum time between two consecutive memory access operations is called the cycle time.
• Data Transfer rate: The maximum amount of information that can be transferred to or from the memory every second is called the data transfer rate.
Main memory or Primary memory
Ø Read only Memory
Ø Random Access Memory
Ø Cache Memory
Read only Memory (ROM)
- Read Only Memory.
- Used for storing programs & data permanently.
- User may read data from ROM but may not write on
- Permanent or Nonvolatile memory
Random Access Memory (RAM)
Ø Temporary storage that can be read from or written into by the user.
Ø Used primarily to store user programs and data.
Ø Temporary or Volatile memory.
Ø Determines a computer’s speed and power
Ø 2 types of RAM:
High speed RAM
SRAM is costly
Does not require refreshing
Requires refreshing periodically
Generally used for cache
Used for main memory