Introduction to operating systems (week 1) Flashcards
What is an operating system?
–> program that acts as an intermediary between the user of a computer and the computer hardware
–> provides an environment in which the user can execute programs in a convenient and efficient manner
–> performs no useful function by itself
studying the operating system helps us to understand the` _______
model of operation
_______ have real value to the person who buys the computer
Application programs
What do computer systems consist of
software and hardware
what are the 2 forms of software
application software and system software
what is application software
–> allows the user to perform some intended task, function, or activity and includes productivity tools.
what is system software
–> provides interface with the hardware
–> serves as a platform for running programs and maintaining the efficiency of the system
–> divided into operating system and utility programs
what does the end user view
application software
for eg: cut, save, print
what does the application programmer view
system software
for eg: malloc(), open(), fork()
what is the OS programmer view
Hardware
for eg: read-disk, track-mouse, start-printer
what are the 2 environments that system software provides
–> allows human users to interact with the computer
–> provides tools and subassemblies used with application programs
system software is __________ to all individual programs
independent
Name 5 things which are part of the system software
–> C library functions
–> A window system
–> database management system
–> command line interpreter
–> OS
what are the 2 parts of the operating system
–> system software
–> trusted os
what is trusted os
the main part of the os which is also called the kernel.
what is a resource
It is anything that is needed by an executing program to run. for eg:
memory
space on disk
cpu
gpu
________ can be viewed as resource manager
operating system
what is resource abstraction
–> OS hides the actual tasks needed to manage and use the resources
–> allows user programs to access these resources by using simpler commands to access these resources
–> makes it easy for user programs to use resources in a computer system
what are examples of resource abstraction
running an application
writing a file to disk
displaying text/graphics on screen
drawback of resource abstraction
simplifies usage but limits flexibility. This is because certain operations become easy to perform while others may be impossible to achieve
what are the 2 kinds of resource sharing
–> space multiplexed sharing
–> Time multiplexed sharing
what is spaced multiplexed sharing
The resource is divided into 2 or more distinct units and each unit is allocated to different processes
what is time multiplexed sharing
The entire resource is allocated to a process for a period of time, after which it is then allocated to another process and so on
what is multiprogramming
refers to the technique for sharing the CPU among runnable processes.
what are some OS strategies that are used to provide the OS services?
batch processing os
timesharing os
personal computer and workstations os
network os
distributed os
process control and real-time os
what is batch processing
–> meant for systems that are resource intensive
–> The same function is going to be repeated many times
–> the work is repetitive and divided into smaller jobs
what are time-sharing systems
–> the computer system has to interact with many different clients at the same time
–> supports interactive client model which gives the illusion of multiple consoles
–> tend to propagate processes
–> considerable attention to resource allocation
enterprise version of linux
red hat linux
_______ is known as open source unix
linux
3 variants of unix
macos
sun solaris
bsd unix
