Week 1 - OS and Linux intro Flashcards
What are the 4 fundamental tasks of a computer?
Input
Process
Output
Store
Explain IPOS Cycle
Input - from user informs computer (program) what to do
Processing - converts data to information
Output - information output so user can view results
Storage - Results can be stored for permanent record
Central Processing Unit (CPU)
Performs the fetch-execute cycle
Fetch next program instruction from
memory
Decode the instruction into actions
Command the relevant part(s) of the
computer to operate to execute the
instruction
Store the result somewhere (if necessary)
What does the CPU consist of?
Control Unit
Handles the fetch execute cycle
Controls the other components of the computer through
signals
Contains registers for important pieces of information like
the memory location of the next instruction
Arithmetic Logic Unit (ALU)
Digital circuits to perform arithmetic and logic operations
Data registers to store data being used by the current set
of instructions
Registers
Data Registers
Program Counter - store location of next program instruction in memory
Instruction Register – store current instruction
Status Flags – store information about last operation
Stack Pointer – store location of the top of the runtime stack where we store information about the
program’s currently executing function
Types of memory from fastest to slowest?
Registers (SRAM)
Cache (on-chip and off-chip), (SRAM)
Main Memory (SRAM)
Secondary storage (hard-disk, optical disk, flash memory)
What is software?
Software are the programs that the computer
runs
– Without software, the computer does
nothing
What is a program?
A program is a step-by-step description of how to perform a task, written in a language the computer can execute
– Machine language
We write programs in easier languages like C++ or Java and convert them into machine
language using a program called a compiler
Input and output devices examples
Input - keyboard, mouse, mic
Output - Monitor, printer, speakers
What is an Operating system?
helps to mediate access to various computer resources, including the CPU, memory, and I/O (input/output) devices.
In other words, the operating system manages the use of these resources by different programs or applications running on the computer.
CPU - which program gets allocated to processor
Memory - What memory can each program use and what to do when memory has ran out - hierarchy.
I/O Devices - Allocated requests from programs for I/O actions and abstracts details of how to interface with device
The operating system is …?
A program that manages hardware and software and is comprised of many components, some loaded into memory and some only loaded when needed.
Core component is the Kernel
What tasks does OS handle?
The OS handles such tasks as
– Process management
– Memory management
– Input/output
– User interface
What is a kernel?
Resource Manager
– Processes
– Memory
Everything Linux DOES is a process
Process: program the kernel launches into memory to do a task
core of Linux OS
Once user initiates a request what happens?
The user does not control computer hardware
The user initiates requests then the OS decides if the user has adequate access rights to perform the requested actions and how to
carry out those actions.
The kernel handles most of the significant operations.
The user interface can be tailored, known as a shell.
Communication with devices is handled through device drivers.
