Zusammenfassung der Ressource
System Softwares
- Operating systems
- Duties
- Managing the use of hardware (inputs
and outputs) across many programs
- Provides an environment
for programs to be executed
- Provides communication
between user and the machines
- Overlooks computer's operations
- Provides
- File management
- stores files in hierarchical structure,storing
a record of their directories
- Memory management
- Memory management: Makes the most
efficient use of RAM. Each task is given a
proportion of the memory and so this allows
many tasks to be able to run at the same time
- Input/Output management
- Queues the requests for the use of the
I/O and executes them in that order
- Processor management
- OS manages which task gets
the next use of the processor
- Data security
- Network and multi user OS can provide
each user with an account followed by a
password, and accessibilty hierarchies
- Types of OS
- Batch processor
- Do repetitive tasks for different data sets. Once initiated with an input, the
Batch OSs is left to procedeed until all iterations are completed. Typically
found in mainframes and typically used for processing paychecks
- Real Time
- Takes in inputs and produces and inputs at different
rates.Immediate updating of files and immediate
response to the user. Examples: car engines, traffic lights
- Single User-Single applications
- Single User - Multiple applications
- Multiple users - multiple applications
- Network OS
- OS that can allow computers to be connected into a network.
- Maintain connection
- logging users on
- Provide security between users
- Utility Programs
- Disk Defragmenter
- Big files may be divided up into smaller fragments
that are stored in a noncontiguous manner,
defragmenters relocate these fragments and any
unused disk space so they can be stored
contiguously for faster accessing speed
- Disk Formatter
- Draws lines on hard disks to create
storage areas for the disk's initial use
- Virus checker
- Constantly find and remove viruses from
sent files, downloaded files and copied files
- Auto backup
- Files can be periodically backed-up on scheduled basis by creating
duplicates of the desired files and folders for servers,
clients, mainframes etc. and stored in alternative
media in the event of hard drive failure
- Compressor
- Reduces file size by removing unwanted parts of a file
which ultimately speeds up computer performance
- Disk content Analyser
- Generate a visual representation of the storage space on the disk
occupied by folders, files and programs, may create graphs to show this.
- System software made to
analyse, maintain and
configure the computer
- Utility programs are
not user-oriented
- Library Programs
- Collection of codes, instructions,
data and resources that can be
used by various programs
- e.g. programs running on Windows 7 all use the same
transparent theme that the windows currently have,
or the system buttons (close, minimise, maximise...)
- Helps the running and development
of more complex software
- DLL: Dynamic Link Library: loaded dynamically into the OS
when a task is needed. It's executable and handle a wide range
of tasks like controlling messageboxes, handling graphics ...
- Advantages
- capable of making advanced programs
- Less time consuming
- Testing becomes less necessary
- Disadvantages
- Some tweaking might be needed for
personalisation - might be tedious
- Prone to virus attacks from
the exposure to various files
- Language Translators
- Assembler: Assembly language
codes into binary (object code)
- Compiler
- Translates HLL into object code all at once
- This is to create an executable program
- Translates all the source code at once
- Leaves the user with the source
code that is about to be executed
- Advantages
- No plaigiarism
from other users
- Easy distribution of .exe code
- Once .exe file is produced, the
compiler software is no longer needed
- execution time faster
than that of interpreter
- Disadvantages
- Slow preparation (translation) time
- If there is a mistake, program wont run or will crash or run
incorrectly therefore the program needs to be error-proof first
- Uses a lot of resources
- Interpreter
- Translates one line
of code at a time
- A translation method of
HLL into object code
- Advantages
- Can be executed before
the entire source code
has been translated
- Less time consuming to translate
- A chance to fix mistakes after the execution of a line (easier to debug)
- Great for prototyping
- Disadvantages
- Execution time slower than compiler
- Since source code is exposed - greater risk of plagiarism
- A full final executable file is not produced