Section 1
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BIOS (Basic Input/Output System)
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Last updated
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Date created
Mar 1, 2020
Cards (69)
Section 1
(50 cards)
BIOS (Basic Input/Output System)
Program that contains low level I/O software (read keyboard, print to screen, etc.) allowing system configuration (Nowadays stored in flash memory)
Stack Segment
Portion of memory used by a program to hold procedure call frames
Command Interpreter
Shells, get and execute the next user-specified command
SSD (Solid-State Drive)
A flash memory storage device that contains its own processor to manage its storage
Address Space
Each process has an associated address space, a list of memory locations from 0 to some maximum, which a process can read and write
Process Table
Array of structures, one for each process currently in existence Stores information about process's state such as: 1. Program counter 2. Stack pointer 3. Memory allocation 4. File handles
Interrupt
A signal that tells the operating system that it is in need of immediate attention
User Mode
A mode in which only a subset of instructions are available
Parallel Bus Architecture
Send each word of data over multiple wires
Busy Waiting
A method by which processes, waiting for an event to occur, continuously test to see if the condition has changed and remain in unproductive, resource consuming wait loops
Shared Bus Architecture
Multiple devices use the same wires to transfer data
Track
Annular region the heads can read
ROM (Read Only Memory)
Nonvolatile chips located on the motherboard into which data or programs have been permanently stored
Cache Hit
When the CPU finds the stored data in the cache
PSW (Program Status Word)
Register that contains code bits, which are set by comparison instructions, the CPU priority, the mode (user/kernel), and various other control bits Plays important role in system calls and I/O
Hard Real-Time System
If an action absolutely must occur at a certain moment (or within a certain range)
Multiprocessor Systems
2 or more CPUs sharing the same physical memory True hardware parallelism
Process
A program in execution
Operating System
Layer of software whose job is to provide user programs with better, simpler, cleaner, model of the computer and to handle managing all the resources just mentioned
Multithreading (Hyperthreading)
Allows the CPU to hold the state of two different threads and then switch back and forth on a nanosecond time scale
Serial Bus Architecture
Sends all bits in a message through a single connection, known as a lane, much like a network packet
Cylinder
Together, all the tracks for a given arm position form a cylinder
Core Image
A suspended processes address space
Multiplexing
Sharing resources in two different ways; in time and space (split time on cpu, or share total resources)
Flash Memory
Type of nonvolatile memory that can be erased electronically and rewritten
Involuntary or voluntary? Fatal error
Involuntary
Kernel Mode (Supervisor mode)
A mode in which the operating system has complete access to all the hardware and can execute any instruction the machine is capable of executing
Multiprogramming
The technique of keeping multiple programs in main memory at the same time, competing for the CPU, increases CPU utilization
Involuntary or voluntary? Normal exit
Voluntary
Daemons
Programs that do not have GUI and run in the background
Virtual Memory
Process of optimizing RAM storage by borrowing hard drive space
Stack Pointer
Register that points to the top of the current stack in memory
Child Process
A process created by another process
Text Segment
The segment of a UNIX object file that contains the machine language code for routines in the source file
Process Termination Conditions:
1. Normal exit (voluntary) 2. Error exit (voluntary) 3. Fatal error (involuntary) 4. Killed by another process (involuntary)
Involuntary or voluntary? Error exit
Voluntary
Spooling
(Simultaneous Peripheral Operation On Line) Load all jobs into main memory and then load each one from memory at a time
L2 Cache
A type of memory cache that is slightly slower than L1 cache, but has a much larger capacity, ranging from 64 KB to 16 MB, stores recently used memory words
DMA (Direct Memory Access) Chip
A chip that can control flow of bits between memory and some controller without constant CPU intervention (cpu creates, when done it creates interrupt)
Cache Lines (often called cache blocks)
The organizational unit of main memory, typically 64 bytes, with addresses 0-63 in cache line 1, 64-127 in cache line 1, etc. Most used cache lines are kept in a cache close to CPU
Context Switch
The exchange of register information that occurs when one process is removed from the CPU and another takes its place
Pseudoparallelism
The illusion of parallelism, processes still run sequentially just at a nanosecond timeframe
System Call
An instruction that interrupts the program being executed and requests a service from the operating system
Program Counter
Register that holds the memory address of the next instruction to be fetched
Interrupt Vector
Address where the CPU starts executing to service an interrupt
Soft Real-Time System
Where missing an occasional deadline, while not desirable, is acceptable and does not cause any permanent damage
L1 Cache
Cache used by a CPU for short-term storage of data and instructions. It is the fastest and closest to the CPU
RAM (Random Access Memory)
Memory modules on the motherboard containing microchips used to temporarily hold data and programs while the CPU processes both. Information in RAM is lost when the PC is turned off (volatile)
Timesharing
A system in which CPU time is shared among multiple interactive users at the same time
Data Segment
The variables
Section 2
(19 cards)