1-2. Client Systems Computers
When an OS manages the computer's memory, the following two broad tasks need to be completed:
1. Each process must have enough memory in which to execute, and it can neither run into the memory space of another process nor be run into by another process. In other words, memory management ensures there is enough memory available to execute programs without interrupting each other. 2. The different types of memory in the system must be used properly so that each process can run most effectively.
The OS, at the simplest level, does the following two things:
1. It manages the hardware and software resources of the computer system. These resources include such things as the processor, memory, disk drives, sound card, and so forth. 2. It provides a stable, consistent way for applications to deal with the hardware without having to know all the details of the hardware.
The task that requires the OS to set up memory boundaries for types of software and for individual applications.
1. Making sure that each process and application receives enough of the processor's time to function properly.
The heart of managing the processor comes down to the following two related issues:
1. Making sure that each process and application receives enough of the processor's time to function properly. 2. Using as many processor cycles for real work as is possible.
six tasks define the core of nearly all OSs
1. Processor management. 2. Memory management. 3. Device management. 4. Storage management. 5. Application interface. 6. User interface.
menu-driven interface
A user interface in which the user chooses a command from menus displayed on the screen.
what is the user's cue to type a command in the command-driven interface .
C:\>.
which interface takes up more of your system's RAM and requires the most power from the microprocessor.
GUI
operational environment
It comes in the form of software and is installed on top of the OS
the active window
It is the only window that is given processing time and it's usually in the foreground while other windows are in the background.
A capability that is characteristic to some OSs is
Multitasking
has become blurred over time
The distinction between an OS and an operating environment
testing and certification.
The major command (MAJCOM) small computer technical center (SCTC) or any other organization designated by the MAJCOM command, control, communications, and computers (C4) systems security office may do
regarded more of a rule than a guideline. A system meeting this requirement will provide basic performance of a software application.
The minimum system requirements
it is the design on the screen which allows the user to interact with the computer to get the results they want.
User interface
The path between the OS and virtually all hardware not on the computer's motherboard goes through a special program called
a driver.
An operational environment is like
a second set of resources added to the OS to provide enhanced services.
The main difference between an OS and an operating environment is that
an operating environment can't run by itself. It is dependent on the OS for resource allocation.
A GUI is designed to
be the most user friendly of all interfaces and emulates the arrangement of your actual desktop.
Much of a driver's function is to
be the translator between the electrical signals of the hardware subsystems and the high-level programming languages of the OS and application programs.
When using a command-driven interface, how does the user makes requests of the system
by typing in commands at a prompt
Applications , with the blocks starting and ending on boundaries established
by words of 4 or 8 bytes.
the user must know what command to use and the correct syntax of the command to use which interface
command-driven interface
The three main types of user interfaces are
command-driven, menu-driven, and graphical user interfaces (GUI)
In a GUI the commands are
displayed as icons or pictorial representations. The user issues commands by selecting icons with a pointing device.
The basic unit of software that the OS deals with in scheduling the work done by the processor is
either a process or a thread depending on the OS
If the block size is 2 KB, then every process that is loaded will be
given a chunk of memory that is a multiple of 2 KB in size.
The distinction between an OS and an operating environment
has become blurred over time
in a command-driven interface It's a good idea to
have a manual readily available to find out what each command is for and when to use it.
how are applications loaded into memory.
in block sizes determined by the OS.
To work with a system, users have to be able to
interact with the system and figure out what it is doing, how to get it to do what they want, and where it is in any process.
The elements that separate one OS from another
its characteristics.
application program interface (API)
lets application programmers use functions of the computer and OS without having to directly keep track of all the details in the CPU's operation.
Before you can install any software on an operational Air Force Automated Information System (AIS),
local security officials must certify that appropriate actions have been taken to ensure the security of the system is not degraded by the addition of the new software.
the OS allows the user to interact with a computer system, almost all OSs are
multitasking
work on two or more separate application programs at one time, or at least what appears to be simultaneous.
multitasking
All public domain software, freeware, and shareware obtained from any source other than an Air Force organization
must be tested and certified before installation on an Air Force AIS.
If the command is typed in wrong in a command-driven interface, the system will
not understand the user's request and the function will not be carried out.
It comes in the form of software and is installed on top of the OS
operational environment
It comes in the form of software and is installed on top of the OS.
operational environment
a second set of resources added to the OS to provide enhanced services.
operational environment
The tasks are
placed in some type of order so the ones with the highest priority are processed
The purpose testing of software is to
provide assurance the software is free of viruses and other forms of malicious code.
A GUI
provides pictures rather than just characters to represent options, programs, and parts of programs.
Also, exceeding by far these requirements does not guarantee to the user that everything will run with absolute smoothness and look its best
recommended system requirements
Although not a necessity, this set of requirements is often sought after by power users who expect to gain a better experience of software usability.
recommended system requirements
More often than not, games are a bit disappointing in this respect, presenting issues that may or may not be corrected with future modifications.
recommended system requirements
it do not promise best possible performance of software and are treated as more of a guideline than a rule. Usually a better system is available, or will be the in future, to provide better performance.
recommended system requirements
For optimal performance of software, vendors often suggest
recommended system requirements.
hardware controlled through drivers,
run when the device is required and function much the same as any other process.
One reason that drivers are separate from the OS is
so that new functions can be added to the driver—and thus to the hardware subsystems—without requiring the OS itself to be modified, recompiled and redistributed.
a process is
software that performs some action and can be controlled by a user, by other applications, or by the OS.
Computers with lower specifications than the minimum requirements may
sometimes run the software, but it is suggested that the user will not have a representative experience of the software this way.
a user interface brings
structure to the interaction between a user and the computer.
To be used efficiently, all computer software needs certain hardware components or other software resources to be present on a computer system. These prerequisites are known as
system requirements or installation requirements and are often used as a guideline as opposed to an absolute rule.
blocks and boundaries help to ensure
that applications won't be loaded on top of one another's space by a poorly calculated bit or two.
Software security products are evaluated and/or assessed by who to ensure the products meet the minimum system security requirements defined by the user.
the National Computer Security Center (NCSC) or the Air Force Research Laboratory (AFRL) or authorized technically-competent organization
It is the only window that is given processing time and it's usually in the foreground while other windows are in the background.
the active window.
We call the window that you are currently working in
the active window.
in terms of using system resources, which user interface is the most beneficial.
the command-driven interface
uses less RAM and less power from the microprocessor than any other interface.
the command-driven interface
The OS will frequently assign high priority blocks to drivers so that
the hardware resource can be released and readied for further use as quickly as possible.
Industry analysts suggest that this trend plays a bigger part in driving upgrades to existing computer systems than technological advancements.
the increasing demand for higher processing power and resources in newer versions of software, system requirements tend to increase over time.
The two sets of system requirements that most software defines are
the minimum and the recommended requirements.
A user interface consists of
the on-screen design or style, the way options are presented, the way commands are issued, and any other item that affects the method of communication.
More than one window may be open, but the only active window is
the one you're working with.
the operating system most prominent characteristics
the operating environments and user interfaces.
The user interface is
the style displayed on-screen that enables the user to interact with the system.
GUIs also use menus
to list some commands.
Air Force organizations that redistribute software must establish appropriate safeguards
to make sure unauthorized persons cannot modify the software.
GUIs provide users with
toolbars that give users a visual shortcut to functions that also exist in the menu structure of a program.
Drivers take data that the OS has defined as a file and
translate them into streams of bits placed in specific locations on storage devices or a series of laser pulses in a printer.
An OS with multitasking capabilities allows you to
work on two or more separate application programs at one time, or at least what appears to be simultaneous.
software certification must include assurances of the following things:
• The local security officials have vested and determined the impact of the new software on system security. • Software is installed and configured according to the Security Features User's Guide or other instructions provided by the software developer. • Local operating instructions (OI) have been reviewed and updated as necessary to accommodate any changes in security procedures required because of the introduction of the new software. • Computer users have been trained on any changes to security operating procedures.
for a software to be usable at all Hardware requirements The most common set of requirements defined by any OS or software applications is the physical computer resources, also known as hardware. A hardware requirements list is often accompanied by a hardware compatibility list (HCL), especially in case of OSs. An HCL lists tested, compatible, and sometimes incompatible hardware devices for a particular OS or application. Various aspects of hardware requirements include its architecture, processing power, memory, secondary storage, display adapter, and peripherals. We will look at each of these in the following paragraphs. Architecture All computers OSs are designed for a particular architecture. Most software applications are limited to a particular OS running on a particular architecture. Although architecture independent OS and applications exist, most need to be recompiled to run on a new architecture. Processing power The power of the CPU is a fundamental system requirement for any software. With software running on the x86 architecture, processing power is defined as the model and the clock speed of the CPU. Many other features of a CPU that influence its speed and power, like bus speed and cache, are often ignored. This definition of power is often erroneous, as CPUs at similar clock speed often have different throughput speeds. The x86 architecture is being phased out in favor of x64 architecture that can support 64 bit OS. Memory All running software resides in the RAM of a computer. Memory requirements are defined after considering demands of the application, OS, supporting software and files, and other running processes. Optimal performance of other unrelated software running on a multitasking computer system is also considered when defining this requirement. Secondary storage Hard disk requirements vary depending on the size of software installation, temporary files created and maintained while installing or running the software, and possible use of swap space (if RAM is insufficient). Display adapter Software requiring a better than average computer graphics display, like graphics editors and high-end games, often define high-end display adapters in the system requirements.
The minimum system requirements must be satisfied
