Programs To Access System Resources.Htm
CHAPTER ONE
NTRODUCTION TO OPERATING SYSTEM
Programs to access system resources (e.g. the CPU, memory, disk,
moderns, printer network an operating system (OS) is a resource
manager. It take the form of a set of software routine that allow users and
application cards etc.) In a safe, efficient and abstract way.
For example, an OS ensure safe access to a printer by allowing only one
application program to send data directly to the printer at any one time.
An OS encourage efficient use of the CPU by suspending programs that
are waiting for I/O operations to complete to make way for program that
can use the CPU more productively. An OS also provides convenient
abstractions (such as file rather than disk locations) which isolate
application programmers and users from the details of the underlying
hardware.
Operating system manage overall activities of a computer and the input
and output device attached to the computer. It is the first software you see
when you turn on the computer, it is the software that enable all program
you use. At the simplest level, an operating system does two things.
The first, it manage the hardware and the software resources of the
computer system. These resource include the processor, memory, disk
space etc.
The second, it provide a stable consistence way for application to deal
with hardware without having to know all the details of the hardware.
1.1 INTRODUCTION TO LINUX OPERATING SYSTEM
Linux was originally developed as a free operating system for personal
computer based on the Intel x86 architecture, but has since been ported to
more computer hardware platform than any other operating system.
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Thanks to its dominance on smartphone, android, which is built on top of
the Linux kernel, has the largest installed base of all general-purpose
operating system. Linux, in its original form, is also the leading operating
system on servers and other big iron system such as mainframe computer
and virtually all fastest supercomputers, bus is used on only around 1.6%
of desktop computer with Linux-based Chrome OS taking about 5% of
the overall and nearly 20% of the sub-$300 notebook sales. Linux also
run on embedded systems, which are device whose operating system is
typically built into the firmware and is highly tailored to the system; this
include the smartphones and tablet computer running Android and other
Linux derivatives, Tivo and similar DVR device, network routers, facility
automation controls, televisions, video game consoles, and smart
watches.
The development of Linux is one of the most prominent example of free
and open-source software collaboration. The underlying source code may
be used, modified and distributed commercially or non-commercially by
anyone under the term of its respective licenses, such as the GNU General
Public License, Typically, Linux is package in a form known as a Linux
distribution, for both desktop and server use. Some of the popular
mainstream Linux distribution are Debian, Ubuntu, Linux Mint, Fedora,
open SUSE, Arch Linux and Gentoo, together with commercial Red Hat
Enterprise Linux and SUSE Linux Enterprise Server distributions. Linux
distribution include the Linux kernel, supporting utilities and libraries,
and usually a large amount of application software to fulfill the
distribution’s intended use.
Distribution oriented toward desktop use typically include a windowing
system, such as X11, Mir or a way land implementation, and an
accompanying desktop environment, such as GNOME or the KDE
software compilation; some distribution may also include a less resource12
intensive
desktop, such as LXDE or Xfce. Distribution intended to run on
servers may omit all graphical environments from the standard install,
and instead include other software to set up and operate a solution stack
such as LAMP. Because Linux is freely redistributable, anyone may
create distribution for any instead use.
1.1.0 FEATUURES OF LINUX OPERATING SYSTEM
Linux has several silence feature, some of the importance ones are:
Multiuser capability: This is a capability of Linux OS where, the same
computer resource – hard disk, memory, etc. are accessible to multiple
users. Of course, not on a single terminal, they are given different
terminals to operate from. A terminal will consist of at least a
monitor/VDU, keyboard and mouse as input device. All the terminals are
then connected to the main Linux sever or Host Machine, whose resource
and connected peripheral device such as printer, can used.
Client /server Architecture is an example of multiuser capability of Linux,
where different clients are connected to a Linux server. The client sends
request to the server with a particular data and server request with the
processed data or the file requested, client terminals is also known as
Dumb Terminals.
Multitasking: Linux has the ability to handle more than one job at a time,
say for example you have executed a command fir sorting for a huge list
and simultaneously typing in a notepad. This is manage by dividing the
CPU time intelligently by implementation of scheduling policies and the
concept of context switching.
Portability: portability was one of the main features that made Linus so
popular among the users, but portability doesn’t mean that it is smaller in
file size and can be carried on pen drive , CD’s and memory cards.
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Instead, here portability means that Linux OS and its application can
work on different types of hardware in the same way. Linux kernel and
application programs support their installation even on every least
hardware configuration.
Security:security is a very important part of any OS, for the
organization/user who is using the system for their confidential
works, Linux does provide several concept for protecting their
users from unauthorized access of their date and system.
Linux is fast, free and easy to use, power laptops and servers
around the world. Linux has many more feature to amaze its
users such as:
Live CD/USB: Almost all Linux distribution have Live CD/USB
feature by which user can run/try the OS even without installing it
on the system.
Graphical user interface (X Window System): People think that
Linux is a command line OS, somewhere its true also but not
necessarily, Linux OS have packages which can be installed to
make the whole OS graphics based as windows.
Support’s most national or customized keyboards: Linux is used
worldwide and hence available in multiple languages, and supports
most of their custom national keyboards.
Application support: Linux has its own software repository from
where users can download and install thousands of applications just
by issuing a command in Linux Terminal or shell. Linux can also
run Windows application if needed.
1.2 CLONING
In computing, a clone is a hardware or software system that is designed to
function in the same way as another system. A specific subset of clone
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are Remark (or Remades), which are revivals of old, obsolete, or
discontinued products.
When IBM announced the IBM PC in 1981, other companies such as
Compaq decide to offer clones of the PC as a legal reimplementation
from the PC’s documentation or reverse engineering. Because most of the
components, except the PC’s BIOS, were publicly available, all Compaq
had to do was reverse-engineer the BIOS. The result was a machine with
better value than the archetype that the machines resembled. The use of
the term “PC clone” to describe IBM PC compatible computer fell out of
the in the 1990s; the class of machine it now describes it now are simply
called PCs. While the term has fallen mostly into commercial disuse, the
term clone for PCs still applies to a PC made to entry-level or above
standard ( at the time it was made ) which bears no commercial branding
(e.g Acer, IBM, HP, Dell). This includes, but is not limited to PC
assembled by home user or Corporate IT Departments.
The components to be cloned are:
SYSTEM CASE
A computer case also known as a computer chassis, tower, system unit
cabinet, base unit or simply case and sometimes incorrectly referred to as
the “CPU” or “hard drive” is the enclosure that contains most of the
components of a computer (usually excluding the display, keyboard and
mouse).
Cases are usually constructed from steel (often SECC –Steel, electrogalvanized,
cold-rolled, coil) or aluminum. Plastic is sometime used, and
other material such as glass, wood and even Lego blocks have appeared
in home –build cases.
POWER SUPPLY UNIT
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A supply unit (PSU) converts main AC to low-voltage regulated DC
power for the internal components of a computer. Modern personal
computer universally use a switched-mode power supply. Some power
supplies have a manual selector for input voltage, while other
automatically adapt to the supply voltage.
SYSTEM UNIT CASE
1.4 MOTHERBOARD
A motherboard is one of the most essential part of a computer system. It
hold together many of the crucial components of a computer, including
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the central processing unit (CPU), memory and connectors for input and
output device. The base of a motherboard consist of a very firm sheet of
non-conductive material, typically some sort of rigid plastic. Thin layers
of copper or aluminum foil, referred to as traces, are printed onto this
sheet. These traces are very narrow and form the circuits between the
various components. In addition to circuits, a motherboard contains a
number sockets and slots to connect the other components.
EXPANSION CARD
The expansion cards (also expansion board, adapter card or accessory
card) in computing is a printed circuit board that can be inserted into an
electrical connector, or expansion slot on a computer motherboard,
backplane or riser card to add functionality to a computer system via the
expansion bus.
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STRORAGE DEVICE
Secondary storage devices are used to save, to backup and even to
transfer files containing of data or programs from one location to another.
We have numerous type of secondary storage such as floppy disk, hard
disk and optical disk.
A data storage device is a device for recording (storing) information
(data). Recording can be done using virtually any form of energy,
spanning from manual muscle power in handwriting, to acoustic vibration
in photographic recording, to electromagnetic energy modulating
magnetic tape and optical discs.
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STORAGE DEVICES
In computer storage, some type of removable media are designed to be
read to or written to by readers, writer and drives.
FLOPPY DISK
FLOPPY DISK
FLOPPY DISK: it is also called diskettes or floopy disk, are portabe or
removable storage media. They are typically used to store, transport word
processing, spreadsheet and other type of files.
Floppy disk are also called flexible disks and floppy because the plastic
disk inside the diskette cover is flexible not rigid, we have traditional and
high capacity floppy disks.
HARD DISK
HARD DISK
Hard disk is unlike a floppy disks that save by altering the magnetic
charges of the disk surface. While a floppy disk uses a thin flexible
plastic disk, a hard disk uses thicker, rigid metallic platters that are
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stacked on top of another, unlike floppy disk, hard disk are able to store
and retrieve information much faster and have a greater capacity.
OPTICAL DISK
OPTICAL DISK
OPTICAL DISK: can hold over 17 gigabytes of data on optical disk
technology, a laser beam alters the surface of a mastic or metallic disk to
represent data. Unlike floppy disk and hard disk, which use magnetic
changes. Optical disk used reflected light the most common types are
compact disk (CD) and Digital Varsities Disk
Optical discs (Blu-ray discs, DVDs, CDs)
Memory cards (Compact Flash cards, Secure Digital Cards, Memory
Stick)
Zip disks/other floppy disks
Disk packs
Magnetic tapes
Paper data storage (punched cards, punched tapes)
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INPUT AND OUTPUT PERIPHERALS
A peripherals is a “device that is used to put information into or get
information out of the computer.”
There are two types of peripherals: input devices, which interact with or
send data to the computer (mouse, keyboard etc.) and output device
which provide output to the users from the computer (monitors, printers
etc.). Some peripherals, such as touchscreen, may combine different
devices into a single hardware component that can be used both as input
and output device.
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