COMP1860 Lecture 8.1 Building our Digital World: Computer Systems & Architecture

Flashcards covering optical memory, magnetic tape, operating systems, and scheduling concepts.

CD-ROM

Optical discs that use similar technology to audio CDs but have better error correction and are made from polycarbonate with microscopic pits storing digital data.

Constant Linear Velocity (CLV)

A method used in CDs where data is packed evenly across the disc, and the disc spins faster near the center and slows down near the edge to ensure data is read at a steady rate.

CD-R

A write-once, read-many CD that uses a dye layer to change reflectivity for permanent data storage.

CD-RW

A rewritable CD that uses phase-change material to switch between crystalline and amorphous states.

Digital Versatile Disks (DVDs)

Optical discs that replaced VHS tapes and CD-ROMs, offering higher picture quality, random access, and more data storage capacity.

Dual-Layer DVDs

DVDs with a second layer of pits and lands above the first, using a semi-reflective layer to allow the laser to adjust focus and read both layers separately.

Magnetic Tape

Storage medium made of plastic film coated with magnetic material, used for storing digital data (computer backups) or analog signals (cassette tapes).

Operating System (OS)

Essential software that manages CPU time, memory, and storage, enabling multi-tasking and improving convenience and efficiency.

Multiprogramming

A technique that allows multiple programs to reside in memory, so when one program waits for I/O, the CPU switches to another, improving CPU utilization.

Time-Sharing Systems

Systems that allow multiple users to interact with the system simultaneously by rapidly switching between user programs, giving each a short time slice.

Long-Term Scheduler

Decides which jobs are admitted into the system for processing and controls the degree of multiprogramming.

Medium-Term Scheduler

Helps control the degree of multiprogramming by swapping processes in and out of memory to optimize resource use.

Short-Term Scheduler (Dispatcher)

Makes frequent decisions on which ready process to execute next.

Process Control Block (PCB)

A data structure maintained by the OS for each process, storing its state and essential execution information.