Презентация, доклад по предмету информатика на английском языке на тему Evolution of operating system

department Theme : Evolution of operating system

3. Simple Batch Systems
4.Operation of Simple Batch Systems
5.Idea of Simple Batch Systems

types of hardware. Examples:
Character vs. graphic terminals
Introduction of paging hardware
Must offer new services, e.g., internet support.
The need to change the OS on regular basis place requirements on it’s design:
modular construction with clean interfaces.
object oriented methodology.

(1970)
Time-Sharing and Real-Time Systems (1970)
Personal/Desktop Computers (1980)
Multiprocessor Systems (1980)
Networked/Distributed Systems (1980)
Web-based Systems (1990)

console.
Paper Tape or Punched cards.

Floating-point), Device Drivers, Compilers, Linkers.
Need significant amount of setup time.
Extremely slow I/O devices.
Very low CPU utilization.
But computer was very secure.

together by type of languages.
An operator was hired to perform the repetitive tasks of loading jobs, starting the computer, and collecting the output (Operator-driven Shop).
It was not feasible for users to inspect memory or patch programs directly.

cards or tape) to a computer operator.
The computer operator place a batch of several jobs on an input device.
A special program, the monitor, manages the execution of each program in the batch.
Monitor utilities are loaded when needed.
“Resident monitor” is always in main memory and available for execution.

execution between user program and the monitor program.
Rely on available hardware to effectively alternate execution from various parts of memory.
Use Automatic Job Sequencing – automatically transfer control from one job when it finishes to another one.

of the job (e.g., Fortran versus Assembly) or which program to execute?
2. How does the monitor distinguish: (a) job from job? (b) data from program?
Solution: Introduce Job Control Language (JCL) and control cards.

distinguish control cards from data or program cards: $ in column 1 // in column 1 and 2 709 in column1

Control Cards (2)

the monitor:
what compiler to use
what data to use
Example of job format: ------->>
$FTN loads the compiler and transfers control to it.
$LOAD loads the object code (in place of compiler).
$RUN transfers control to user program.

$JOB
$FTN
...
FORTRAN
program
...
$LOAD
$RUN
...
Data
...
$END

causes one line of input to be read.
Causes (OS) input routine to be invoked:
checks for not reading a JCL line.
skip to the next JCL line at completion of user program.

is in monitor.
loads next program and transfers control to it.
when job completes, the control transfers back to monitor.
Automatically transfers control from one job to another, no idle time between programs.

carrying out instructions on the cards.
Loader – loads systems programs and applications programs into memory.
Device drivers – know special characteristics and properties for each of the system’s I/O devices.

Resident Monitor Parts

monitor to be altered by a user program.
Privileged instructions
can be executed only by the resident monitor.
A trap occurs if a program tries these instructions.
Interrupts
provide flexibility for relinquishing control to and regaining control from user programs.
Timer interrupts prevent a job from monopolizing the system.

CPU could not overlap.
Solution: Offline Operation (Satellite Computers) –
speed up computation by loading jobs into memory from tapes while card reading and line printing is done off-line using smaller machines.

to Disk).
I/O and CPU could not overlap.
Solution: Spooling -
Overlap I/O of one job with the computation of another job (using double buffering, DMA, etc).
Technique is called SPOOLing: Simultaneous Peripheral Operation On Line.

reader into a storage area on the disk (Job pool).
Outputs printout of previous job from disk to printer.


Job pool – data structure that allows the OS to select which job to run next in order to increase CPU utilization.

instruction execution).
A program containing even a very small number of I/O operations, will spend most of its time waiting for them.
Hence: poor CPU usage when only one program is present in memory.

keep CPU and I/O devices busy at all times.
Multiprogramming organizes jobs (code and data) so CPU always has one to execute.
A subset of total jobs in system is kept in memory.
One job selected and run via job scheduling.
When it has to wait (for I/O for example), OS switches to another job.

instructions while I/O device is busy.
Timer interrupts for CPU to gain control.
Memory management
several ready-to-run jobs must be kept in memory.
Memory protection (data and programs).
Software support from the OS:
For scheduling (which program is to be run next).
To manage resource contention.

publication by Robert Patrick
3."Timeline of Computer History: 1956: Software". Computer History Museum. Retrieved 2008-05-25.
4.A Brief History of Linux
Johnston (April 1, 2005). "VSE: A Look at the Past 40 Years". z/Journal. Thomas 5.Communications, Inc. (April/May 2005).
Chuck Boyer, The 360 Revolution