Systems Security Architecture

RAM – Random Access Memory
ROM – Read Only Memory
PROM – Programmable ROM ( Non volatile)
EPROM – Erasable PROM (erased via ultra-violet light)
EEPROM – Electrically Erasable PROM (erased by electrical charge instead of light)
PLD – Programmable Logic Device (Electronic device used to build digital circuits. Combination of memory and logic like flash memory and SRAM)
Secondary Storage – Optical drives, Tapes, NFS, internal or External HD
Cache – Small amount of high speed RAM
Virtual Memory – Pseudo memory works off of secondary storage. Adjustable
Sequential Access Storage – Reading and/or writing in sequential order. To read record 10 you would have to read 1-9 first.
Random Access Storage – Ability to access data at random. Going directly to the point like a disk drive.

Instruction Execution

  • Fetch and Execute Phases
  • Operating, Application, Supervisory, Wait States
  • Privileged Instructions in supervisory state
  • User mode in Operating & Application states

CISC and RISC ( Complex Instruction Set Computing (normal cpus) and Reduced Instruction Set Computing (special funstion chips)


  • DMA – Direct Memory Access for peripheral devices avoiding the cpu.
  • Channels link the memory and Peripherals
  • Interrupt Processing (Potential security risk)


  • Operating System and Software
  • High Level Language – (what op or app is written in like perl or vb)
  • Assembly Language – (still human readable language or mnemonics)
  • Machine Language – (string of binary)