Topic 6 - Resource Management Student Booklet

8/18/2019 Topic 6 - Resource Management Student Booklet

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Topic 6 - Resource management Student Booklet

Resource Management

by M Brooke

System resources

6.1.1 Identify the resources that need to be managed within a computer system.

Key Terms

● Primary memory● RAM


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● Secondary storage● Magnetic storage● Solid State Drive● Optical Storage● Hz● Bandwidth● bits per second● Screen resolution● Pixels per inch

● Sound processor ● Graphics processor ● Cache● Network card● Fibre optic● Ethernet

Primary memory

Primary storage also known as main storage is an area where data is stored for quick retrieval by theCPU. Random Access Memory (RAM) is an example of this. RAM is temporary memory (volatilememory) that is lost when the system is shut down.The RAM contains all the current process of the system such as the operating system, and any other software or processes that are currently running. In order to save the data more permanently the datamust be written to secondary storage such as a hard disk.RAM is made up of integrated circuits. There are different types of RAM such as SRAM DRAM and

SDRAM[1] . The more RAM a system has the more memory it has available for running processes. A personal computer or laptop with more RAM will allow the user to be able to run more programs atthe same time or to be able to run memory intensive programs such as video games.

Secondary storage

Secondary storage is used in a computer system for long term memory storage. In contrast to RAM itis non volatile (data is retained when the system is sut down). Secondary storage can be done using

several types of media for example:[2]

● Magnetic storage○ Hard disk drive○ Magnetic tape

● Optical storage○ Blu Ray○ DVD○ CD

● Integrated circuits○ Solid state hard drive


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Processor speed

The speed of a processor is normally measured in Hertz (Hz). For most processors this is in GHz. For

example the speed of one type of Intel i7 chip is 4.00 GHz [3] 1 GHz is approximately 1 billion Hz.

This means that the CPU can perform 1 billion actions per second. For computers such assupercomputers the speed is often measured in Floating Point Operations Per Second (FLOPS). For

example the Tianhe-2 can perform a about 55000 TFLOPS/S. [4]

Bandwidth

The term bandwidth describes how many bits can be transferred in time over a specific medium. Thisis normally measured in bits per second. Internet connect ions are normally expressed as megabits

per second (Mbps). The bandwidth of a network can be improved by using optical fibre cables [5]

which allow a higher bandwidth compared to standard ethernet cables such as Cat-5 or Cat-6[6] .Internet service providers will generally offer two tiers of provision namely ADSL which uses existingtelephone lines to transfer data. This runs at a maximum of 24Mbps. Alternatively many companies

now provide a fibre optic or cable service which runs at much higher bandwidths up to 100Mbps [7]

.

Screen resolution

Screen resolution relates to the number of pixels that a screen can display. It is normally expressed in

terms of horizontal pixels by vertical pixels. For example an HD display would be 1920x1080. Often

referred to as 1080p. The diagram below compares the most common screen resolutions. [8]


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Screen resolution also relates to screen size. A screen of high resolution and small size will have ahigh pixels per inch (PPI).

Disk storage

Sound Processor

A sound processor also known as a sound card or an audio card is an internal component of acomputer system that deals with the input and output of audio signals. These are sometimes built intothe motherboard vut can also be a discreet card that slots into the motherboard or a peripheral devicethat connects to a high speed port on the system such as USBx or Firewire.

Often the processor will have to deal with the analogue to digital and digital to analogue conversion(ADC/DAC). On most computers this will be a low cost solution with a headphone and microphonesocket. Professional music studios require a much higher specification and will require sophisticateddevices to handle the processing.

Graphics processor

A graphics processor also known as a graphics card or video card is an internal component of acomputer system that deals ith the graphical input and output. These can be onboard graphics built

into the chipset

[9]

or can be a card that is slotted into the motherboard such as an NVIDEAgraphics card shown below [10] .


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Cache

Cache is a small amount of very fast memory that is used by the CPU to retrieve data to speed upprocessing. The cache sits between the CPU and the main memory (RAM). This is explained in more

detail in 2.1.3. [11]

Network connectivity

Network connectivity can be managed by any number of devices such as the network card thatconnects the computer to the network cables, switches, hubs and bridges that connect the networktogether and routers and servers that provide connection to eternal networks. This is all covered in

more detail in Topic 3 - Networks [12]

6.1.2 Evaluate the resources available in a variety of computer systems.

Key Terms

● Mainframe● Server ● PC● Laptop● Cell phone● PDA● Digital cameras

Supercomputer

A supercomputer is a computer at the frontline of current processing capacity, particularly speed of calculation. Supercomputers are used for highly calculation-intensive tasks such as problems


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including quantum physics, weather forecasting, climate research, oil and gas exploration, molecular

modeling. [13]

Mainframe

A very large and expensive computer capable of supporting hundreds, or even thousands, of userssimultaneously. In the hierarchy that starts with a simple microprocessor (in watches, for example) at

the bottom and moves to supercomputers at the top, mainframes are just below supercomputers. Insome ways, mainframes are more powerful than supercomputers because they support more

simultaneous programs. [14]

Servers

A computer or device on a network that manages network resources. [15] There are many differenttypes of servers. For example:

● File server ● Print server● Database server ●●

PCs

A personal computer (PC) is any general-purpose computer whose size, capabilities, and original

sales price make it useful for individuals, and which is intended to be operated directly by an end-user

with no intervening computer operator.[16]

Laptops

A laptop computer is a personal computer for mobile use. A laptop integrates most of the typicalcomponents of a desktop computer, including a display, a keyboard, a pointing device such as a

touchpad (also known as a trackpad) and/or a pointing stick, and speakers into a single unit.[17]

PDAs

A palm-top computer that functions as a personal organizer but also provides email and Internetaccess.

Cell phones

A mobile telephone system using low-powered radio transmitters, with each transmitter covering a

distinct geographical area (cell) and computer equipment to switch a call from one area to another,thus enabling large-scale car or portable phone service.[18]

Digital cameras


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A camera that records and stores digital images.Develop an appreciation of the issues linked to resource availability with continued developments incomputer systems.

6.1.3 Identify the limitations of a range of resources in a specifiedcomputer system.

For example, single processor computers may not be able torender 3D graphics effectively.

6.1.4 Describe the possible problems resulting from the limitations in theresources in a computer system.

For example, user time wasted if the primary memory is too small or processor speed inadequate.Multi-access and multiprogrammingenvironments shouldbe considered as well as single-user systems.

Role of the operating system

6.1.5 Explain the role of the operating system in terms of managingmemory, peripherals and hardware interfaces.

The operating system

6.1.5 Explain the role of the operating system in terms of managing memory,peripherals and hardware interfaces.

Key Terms

● Operating System● Kernel● Device Driver ● Virtual memory● Multitasking

● GUI● Peripheral

The operating system has many roles such as: [19]

● Kernel○ Program execution


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○ Interrupts○ Modes○ Memory management○ Virtual memory○ Multitasking○ Disk access and file systems○ Device drivers

● Networking● Security

● User interface○ Graphical user interfaces

Managing memory

The operating system manages all memory currently in use by programs ensuring that there are nono memory conflicts. In addition to this there is an element of memory protection stops applicationsusing too much memory.In addition to this the operating syste will also manage the secondary storage. This is done using fileallocation tables that keep track of where data is stored. This can be done using systems such as

FAT32 or NTFS [20] .

Time slicing

Time slicing is related to multitasking where is appears that the computer is able to run more than onetask concurrently. It actually does this by allocating time slices to the various processes. The key tomultitasking is time slicing coupled with good memory management. Time slicing simply makes use of the speed of a modern processor to make it look as if more than one thing is happening at a time.The operating system loads application programs one at a time into memory and maintains a list of

active “tasks”.It then allocates a time slice – usually 1/10th of a second or thereabouts – to the first task in the list.When the time slice is up then the next application in the list gets a time slice allocated to it and so onuntil all of the applications in the list have had a time slice and the process starts over at the beginningof the list.

Peripherals

A device driver is a specific type of computer software developed to allow interaction with peripheralhardware devices.


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6.1.7 Outline OS resource management techniques: scheduling, policies,multitasking, virtual memory, paging, interrupt, polling.

Key Terms

● Scheduling● Policies● Multitasking● Virtual memory● Paging● Interrupt● Polling

Technical details as to how these are carried out will not be required, but it is expected that students

will be familiar with these techniques and understand when and why they are used.

Scheduling


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This is the method to which threads, processes or data flows are given access to system resources. The need for scheduling is mainly to service the requirements of multitasking systems. When one or more process are set to run the OS must decide which one is first. There are several factors that needto be considered in order to assess what scheduling algoirithm is required.

● Throughput○ Maximising the number of jobs in a time unit

● Latency○ Time taken to complete tasks

● Fairness

○ Appropriate times according to each process' priorityThe different types of scheduling are assessed below in the table.

Scheduling algorithm CPUOverhead

Turnaround time Throughput Responsetime

First In First Out Low High Low Low

Shortest job first Medium Medium High Medium

Priority basedscheduling

Medium High Low High

Round-robin scheduling High Medium Medium High

Multilevel Queuescheduling

High Medium High Medium

Policies

Multitasking

Multitasking refers to the running of multiple independent computer programs on the same computer;giving the appearance that it is performing the tasks at the same time.Since most computers can do at most one or two things at one time, this is generally done via time-sharing, which means that each program uses a share of the computer's time to execute.

An operating system kernel contains a piece of software called a scheduler which determines howmuch time each program will spend executing, and in which order execution control should be passedto programs.

Virtual memory

The operating system is responsible for managing the memory of the system to ensure that there areno conflicts of memory usage between all the currently running programs and processes. This cansometimes involve using a portion of the disk drive as primary memory. This has major drawbacks asthe speed of a hard disk is several orders slower than main memory. Each piece of memory data isgiven a virtual address. This may translate into a physical address in primary or secondary memory.


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Paging

In computer operating systems, paging is a memory-management scheme by which a computer canstore and retrieve data to and from physical storage for use in virtual memory. In the paging memory-

management scheme, the operating system retrieves data from physical memory in same-size blockscalled pages.The main advantage of paging over memory segmentation is that it allows the physical address spaceof a process to be noncontiguous. Before paging came into use, systems had to fit whole programsinto storage contiguously, which caused various storage and fragmentation problems.

Interrupt and Polling

An interrupt is a signal sent from a hardware device or an application to the microprocessor toindicate that attention (a service) is required.

Polling systems check each peripheral in turn to see if a service is required by that device. This is lessefficient than an interrupt system


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6.1.8 Discuss the advantages of producing a dedicated operating systemfor a device.

Advantages related to size, speedand customization should beconsidered.For example, using a dedicatedoperating system for a cell phonerather than using a pre-existing

operating system.S/E Issue of proprietary software.

6.1.9 Outline how an operating system hides the complexity of thehardware from users and applications.

Users and applications do not see the hardware directly, but view it through the operating system. Applications and users view the hardware through the OS.This is used to hide certain hardwaredetails from users and applications. Due to this abstraction, users cannot see changes in the

hardware. For example, interaction with 3D graphics hardware can be controlled by the operatingsystem. Another way that abstraction can be used is to make related devices appear the same fromthe user point of view. For example, hard disks, floppy disks, CD-ROMs, and even tape are all verydifferent media, but in many operating systems they appear the same to the user.


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Drive letters

Also referred to as a device letter, a drive letter is a single alphabetic character A through Z that hasbeen assigned to a physical drive or drive partition in the computer. For example, a computer with a 31/2" floppy diskette drive has a drive letter of A: assigned to the drive. All computers with a hard drivewill always have that default hard drive assigned to a C: drive letter and the CD-ROM or other discdrive is the last drive letter (e.g. D:).

On a network virtual drives are also named in a similar fashion but the complexity of the network ishidden and the drive assigned a virtual drive letter so it appears the same as a normal drive to theuser.

The Java Virtual Machine (JVM)

A Java virtual machine (JVM), an implementation of the Java Virtual Machine Specification, interpretscompiled Java binary code (called bytecode) for a computer's processor (or "hardware platform") so

that it can perform a Java program's instructions.[21]


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Through the JVM an application is capable of running on a number of platforms.

Now test yourself

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Michael Brooke emjbe.net

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Topic 6 - Resource Management Student Booklet

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