cse1720 summer 2005 lecture 03 /1 lecture no. 3 software systems, memory management throughput,...

CSE1720 Summer 2005 Lecture 03 /1

Lecture No. 3

Software Systems, Memory ManagementThroughput, Instruction Execution


Objectives

• To look at Software- Operating systems- Applications Systems

• Microcomputer Operating Systems• Commands and Command Structures• Main Memory Considerations including Management• Throughput Aspects• Instruction Execution

And, some more on Excel


Computer Software

SYSTEM APPLICATIONSOFTWARE SOFTWARE

DatabaseManagement

Communications Control

Operating Systems

BusinessApplications

ScientificApplications

Other Applications

SoftwarePackages

*

Systems ApplicationsSoftware Software


Functions of an Operating System

An operating system is software that controls the computer by:

managing resources providing services for

programmers scheduling execution

Computer Hardware

Operating System

Utilities

ApplicationPrograms

EndUser


Operating Systems

• Are a collection of systems programs

• Designed to co-ordinate and control the overall operation of computer hardware and software

• An Interface between the Hardware and the Application

• Designed to manage RESOURCES: - C.P.U - Input Devices - Output Devices - Storage Devices (including Memory)


Operating Systems

• Designed to communicate with the USER when necessary - error in job

- no input device available- no output device available- insufficient storage/memory- end of job

• Designed to boot the computer system - start the computer operation

• Provides a means of Security


Operating Systems

LanguageTranslators

Service Programs

OtherProcessingPrograms

Control Programs Processing Programs

JobManagement

ResourceManagement

DataManagement


Operating Systems -Additional FeaturesOverlapped Processing

Dynamic processing Multiprogramming Virtual memory Virtual Machines

MODERN OPERATING SYSTEMS

INTERACTIVE BACKGROUND REMOTE COMMUNICATION TASKS TASKS TASKS TASKSConversational Scheduled Remote Inquiry/ResponseComputing Jobs Job Entry Interactive Non-Scheduled TimesharingProgramming Jobs


System Software Capabilities

• Multitasking : an operating system which handles more than one program at a time

• Multiprocessing : an operating system which handles two or more CPUs to process simultaneously

• Timesharing : an operating system which supports a front-end processor to schedule and

control users’ processing requests• Virtual Memory : an operating system element which

enables a computer to process as if it had

an unlimited supply of internal memory


Microcomputer Operating System

Normally - A single user ( May be multiples on larger units e.g. PS/2 with OS/2)

- System driven by user - Functions Interactive

- User Controls * File Usage * Backup and Recovery * Process functions

- User applies (develops) usage ‘standards’ - Assisted by the Operating System


Microcomputer Operating System

Some Terms to Note :

DIRECTORY - An Allocation of Disk Space for user requirements

FAT - File Allocation Table - An index of disk contents with track and sector addresses

TOC - Table of Contents - Table of disk contents

NOTE: Physical Handling of Diskettes

Storage of Diskettes - Formatting


Systems Software Components

• Internal Command Instructions

• External Command Instructions

• Language Processors Cobol, C, C++, Delphi, Oracle Developer, Oracle Designer,

Java, JavaB , Powerbuilder,

Is SAP a ‘language’ ?


Internal Command Instructions

Normally are resident in memory after Operating System loads

• View a list of the files on your disk storage device (Win NT / 2000 / XP Explorer) • Copy files from one disk device to another

• Erase files


External Commands

Are retrieved from secondary storage (disk) then executed

• Format disk

• Rename files

• Set the current date format (mm-dd-yy, dd-mon-yy

• Set the current time (12 hour, 24 hour, time zone)

• Print


Command StructureA ‘command’ sets up a process or a series of processes

A command must have

- a command code (dir, erase, copy, paste …..)

- one argument (for some commands - qualifies the command e.g. Dir a: dir c:\studies\assignment1.doc

- a second argument (where necessary)e.g. copy xxxxx to a:\yyyyy add zzzzz to mmmm


Microcomputer Operating Systems

• Apple DOS MS-DOS (v6.22)

• OS/2 and OS/2 Warp • SunOS • HP-UX

• Unix, Ultrix, Linux

• Microsoft Windows95 Windows NTWindows98 Windows2000 WindowsXP ? Windows2003 ?

Operating systems for Larger Installations• VMS, MVS, OS390, OSF/2, VX24, ............


A Competitor to Windows - Linux

It is an operating system for serversIt runs on all modern computer architecturesIt runs on clusters and Cray machinesIt is free of licence costsIt appears to be a single, unifying platform with write-once,

run anywhere capabilitiesIt is not co-opted or owned by a single entity, corporation or

governmentSupport a number of graphical user interfacesIs available from several Web sites - Linux kernel, system

utilities, applications and an installer


Selection of Systems Software

• Availability of compatible applications software and/orsystems

• The ease of use by users and programmers ( = help)• Speed of operation• Capability to support multitasking and multiuser needs• Type and availability of compatible hardware• Availability of trained and available technical staff• Company size and market penetration• Other users’ comments


Applications Software

• General Business Management

• Industry Specific

• Specific Disciplines

• Education

• Personal/Home Management

• General Purpose software for the user


Software Packages

Word Processing

Spreadsheets

Graphics and Multi Media

Database Management Systems

Integrated Software SAP, Oracle Financials

Application Enterprise Integration (probably with PCs as clients)


Internal Mechanisms

• None of this just ‘happens’

• Computers rely on a number of agents, devices, processes, interpreters, flows and controls to operate effectively, accurately and consistently

• So, let’s look at some of these aspects ---


Some Thoughts on Chips

Computers rely on chips and chip technology for their

processing capabilities storage capabilities We will briefly look at some of their characteristics, function

and types in the following overheads


Chips and Microprocessors

Every microprocessor’s system unit has a specific microprocessor chip (as per the 1st lecture - Intel, Motorola, Cyrix, AMD)

This microprocessor chip is embedded in a carrier package

The carrier is mounted on a system board - ‘motherboard’

Software is optimised to work on a specific chip (or family)

Software developed for a Pentium ll chip probably won’t work on an 80386 or 80486 chip

What about Pentium 4 on a Pentium l or 2 ?


Chips

Word size:

A word is a group of bits (binary digits) - also called bytes - which can be manipulated as a unit by a processor

The Pentium Pro has an internal bus designed for 64 bit words (data moves in the chip in 64-bit blocks)

The Pentium Pro data bus also handles 64 bit words.

This means that the data path from the CPU to memory is 64-bits wide - the benefit is faster processing


Chips

• Most PC’s have specialised processor chips

• Numeric processors• Graphic coprocessors

• Normally known as slave chips

– Their function is to free the CPU from some processing tasks.

– The overall effect is improved system performance


Chips

Now let’s look at the ‘data’ storage components

The normal term for this is ‘Main Memory’ - which infers that there is a lower level of memory as well

The ‘memory’ chips - RAM (Random Access Memory) are circuits etched onto silicon backed chips.

These also are mounted in carriers and are arranged onto boards called single in-line memory modules - SIMMs

These units also plug into the system (mother) board


Main Memory and Its Uses

• To store the main software which controls the general operation of the computer system

• To store a copy of application program instructions

• To store data which has been input from an input device

• To store data which has been produced as a result of processing


Main Memory and Its Use

ROMRAM

ROM

DOS/WINDOWS

RAM

RAM

DOS/WINDOWS

ROM

Excel V5

No memory contents

Operating SystemLoaded

Operating Systemand ApplicationSoftware Loaded


Main Memory (Primary Storage)Diagrammatic Representation

INPUT AREAOUTPUT AREA

OPERATING SYSTEM

SPECIAL SOFTWAREDatabase Management SystemCommunications Software (Telnet,Netware)

APPLICATIONS PROGRAM(S)

Spare / Work AreaInterrupt Storage Area (Stacks)

(not to scale)

RAMDRAMSCRAMFRAM

ROMPROMEROMEPROM


Operating System Layout Hewlett Packhard PC

Operating system RAM ImagesOperating System Dynamic RAM Pool User Access RAM Pool

Process 1Process 2

Process ....n

Memory Management Unit: Disk Keyboard Graphics Processing Beeper Clock Memory Control Registers Plug In I/O Cards

Basic ROMROM DISKOperating System ROM

(physical)

Internal RAM

External RAM

I/O

ROM

16M

15M

8M

1M


Tomorrow …...We are going to continue with aspects of

Memory managementMemory storageCache ChipsBusesWindows NT, 2000 and XP

But now, we’re off for a bit more of Excel.


Spreadsheet SolutionSome Hints

What is the problem ? What am I trying to solve ? Why ?

• What formulae are appropriate - necessary ?

• What is the data input - is it fixed ? Is it likely to vary ?

• Where is it ? In a file ? Via the keyboard, In a Range ?

• What is its definition ? - Text, label, date, formatted, edited ?



• Is there an opportunity/need for cascade calculations ?

• How are the embedded formulae addresses to be used

• What is the degree of accuracy required e.g. 1 Decimal. Place

• Do I know how to use the built in HELP ? And does it give

me sufficient to assist me solve my requirement ?



• Graphs /Charts: Is there an opportunity to display input or output in graphical form ?

• Which Chart best represents the objective of the spreadsheet

• What name should the Chart have ? What Axes names are appropriate ? What scale ? Will 3 D and colour enhance the presentation



• Should the chart be embedded in the spreadsheet or in a separate sheet ? Why ? How should it be protected ?

• Are there some repetitive activities which can be made automatic, or require less key strokes - or made user proof ? Is it worth while to create a Macro ?



• How should the spreadsheet best be stored ?In the current Directory / Drive ?

• Should a copy be made ? If so, how will the copy be kept up to date ( e.g. include in a Macro)

• Should more than 1 copy be made ? Where should it/they be held for recovery and security reasons ?



• Who should be able to use the spreadsheet ?

• Who should be able to alter data / formulae ?

• How can access to the spreadsheet be made secure ?

• Who will be Managing the security aspects ? (and a Deputy ?)


Developing / Using Spreadsheets

• Decide on the approach to the problem• Define Formulae• Define Cell Contents• Enter Data - CORRECTLY !! - labels, text, numeric ...• Manipulate data• Develop Output / Results• Produce Output

***************** ****************• Analyse Results• Refine, Re-Enter (Recursive)• Re-specify as necessary• Re-Evaluate


Some Aspects of Using Spreadsheets



Some Commonly Occurring WEAKNESSES !• Logic Mistakes• Incorrect Ranges in Formulae References• Incorrect Cell References• Incorrect use of FORMATS and COLUMN WIDTHS• Misuse of Built - In Functions• Overwriting of Formulae• Lack of Data Protection• Undetected Access• Data Integrity• Input Errors - Error Detection



SPREADSHEET DESIGN• Requires some experience with a computing device• Requires an understanding of programming techniques

and disciplines• Requires testing - Strategy, Results Analysis• Documentation

OBJECTIVES OF DESIGN:RELIABILITYAUDIT CAPABILITYCONTROL


Spreadsheet Design Objectives

• All OUTPUTS GENERATED ARE Correct Consistent• Results are RELIABLE• There is an AUDIT Capability meaning that the user

should be able to retrace the steps followed to generate different outputs from the model - and be able to verify results (see Precedents in Excel)

• The spreadsheet can be Modified without the introduction of errors

• The spreadsheet is meaningful and understandable to both the Designer and the User


Typical Spreadsheet Applications

• Decision Support for ? ? ?

• Personal Productivity

• Mainstream Information Systems Financial Statements Budget Planning Budget Control Taxation


SPREADSHEET DEVELOPMENT LIFE CYCLESPREADSHEET DEVELOPMENT LIFE CYCLE

• 1 Problem Definition - Analysis

• 2 Define: Model Outcome Decision Variables Calculations Menus Macros

• 3 Construct the model


SPREADSHEET DEVELOPMENT LIFE CYCLESPREADSHEET DEVELOPMENT LIFE CYCLE

• 4 Test

• 5 Document

• 6 Audit

• 7 Prepare User Manual

• 8 Train Users

• 9 Install


IdentifyProblem

Define ModelOutcome/Decision Variables

ConstructModel

TestSpreadsheet

Document

Audit Model andStructure

Prepare UserManual

TrainInstall


Model Format

AIMS• 1 To identify the spreadsheet and its purpose

• 2 To clarify assumptions for users

• 3 To separate parts of a spreadsheet to reduce potential for errors

• 4 To allow for progressive development


Model Format

• Macros and Menus are ISOLATED from parameters and Formulae to avoid interference from Delete/Insert of Rows and/or Columns

• Map of Model This gives a description of the positioning of the Blocks of the Spreadsheet -candidates are range names, cell addresses,

• Acts as a Table of Contents

• Parameter Block This contains variables used in the spreadsheet formulae (e.g. Sales Prices, Cost Prices, Hourly Rates, Maximum and Minimum, ..........


Model Profile

* Identification* Owner Macros* Developer Menus* User* Date Revised* File names (Spreadsheet, Backup,

Map of Model - Table of Contents

Parameters and Assumptions e.g. percentages are dependent on the cpi.Model - Formulae Input Vectors Decision Variables Output Vectors Parameter Vectors


Monash Agri-Business

Percentage of Nutrient in Minimum Amount inNutrient Feed 1 Feed 2 Feed 3 Feed 4 Required Amount BlendCorn 30.00% 5.00% 20.00% 10.00% 20.00% 0.00%Grain 10.00% 30.00% 15.00% 10.00% 15.00% 0.00%Minerals 20.00% 20.00% 20.00% 30.00% 15.00% 0.00%Kilograms to mix(in 1,000's) 0 0 0 0 8 0

Cost per $250.00 $300.00 $320.00 $150.00 $0.001,000kgs

A B C D E F G H I J

1

2

3

4

5

7

6

8

9

10

11

12


Spreadsheet Assignment Hints

1. Easy to read and accurate layout

The first page (screen) should have references to Documentation : Spreadsheet Name Developer’s Name and I.D. Purpose of the spreadsheet Date (completed or submitted) Files Used ( ALL files and their purpose AND their location - access path)


MONASH UNIVERSITY 2nd Semester, 1998

Student I.DStudent NameSubject CodeDate Prepared

Spreadsheet Objective

AssumptionsData AreaResultsConstraintsFile names - Original - Active -Backup



2. Location of : Input Areas Output Areas Results Charts or Graphs Analysis report (if this is required) Contents of Individual sheets

(These details may be combined with the First Screen)



3. Contents of ComponentsInput data area - tablesOutput data area - tablesChart(s)ModelFormulae - any built in functions used

4. Any constraints - roundings, limitation of time series Options used with built in functions - such as the

nomination of repayment at beginning or end of month



Presentation Of Charts

• Must have a meaningful name - not ‘results’

• Use legends, X and Y axes names

• Use colours

• Use an appropriate chart form

• Use multiple charts if necessary to better illustrate results


Excel Special Functions


Spreadsheet Functions by Category

Database and List Management (dsum, dstdevp, daverage..)

Date and Time (now, Month, Day, Datevalue ...)DDE and External (upper, dollsr, floor, gcd..)Engineering (radians, odd, Poisson,hypgeodist)Financial ( PMT, PPMT, RATE, TBILLPRICE, NPV, ..)Information ( Average, Min, Max, ..)Logical (and, or, if, isodd, isref ...)Lookup and Reference (index, vlookup, hlookup, lookup .)Mathematics and Trigonometry (acosh, bin2oct, correl, log ..)Statistical (dstdev, stdev, normdist, percentile , prob ....)Text (char, code, concatenate, count, counta, N, right, left ..)


Your Spreadsheet Skills• INTERMEDIATE LEVEL

Load spreadsheet softwareSet Directory PathsFile Functions - Save As, Save, Retrieve, Copy, Delete,

Inspect (File Manager functions)Enter Text, Labels, FormulaeAlter column specifications - width, height on a Local and Global basisInsert / Delete Rows, ColumnsCreate / Name Cell RangesCopy Cell Range to Cell RangeMove Cell RangesDelete Worksheet


Your Spreadsheet Skills

Function Key use - F4, F9, F1, F2 ......Formulae Development and EmbeddingUse of Special Keys - Control+Home, Ctrl+End, Tab, ...FormattingEditingCloseExit (and the dialog box responses)ChartingSortingData Base FunctionsCombining SpreadsheetsSplitting WorksheetsData Fill, Series, Frequency, ...........


Compound Functions


Assessment Rules

• The Rules for Assessment of student marks are:

1. A student must obtain an overall average of 50% to pass the subject

2. A student must obtain a minimum of 40% in the Examination or the Practical Assessment

3. The final mark shall be the lesser of the marks for the 2 Components , plus 10


Spreadsheet Application

Assume that

The marks for the Examination are in cell A65

The marks for the Practical Work are in cell A66

The Total Mark is in cell A68

An Intermediate Cell is used to detect the 40% rule - cell A67

The FINAL ADJUSTED MARK is in cell A70



The IF statement coupled with the OR option provides the basis of preliminary assessment.

Part 1. To assess if the 40% rule has been met:

The Formula will be in Cell A67

IF(OR(A65<39.9,A66<39.9),1,0) - This puts a 1 in A67 if there has been a result of <40% in either component,

and a 0 in A67 if there has not been a result of <40%

(what about the use of =<40% ??)



Before we proceed we need to build a ‘decision table’ based on results:Prac Work Examination Result Grade

a b c 0 > 50 10 N

>50 0 10 N 30 > 50 40 N 42 > 50 52 P 50 60 55 P (Average) 60 90 70 C (Min + 10) 45 90 55 P (Min + 10)



Prac Work Examination Result Grade a b c

20 20 20 N 39 39 39 N 0 0 0 N 15 39 25 or 39 ? 5 55 15 N

All other cases of > 50 are averaged.



What is necessary is to combine these conditions into an Excel command which will provide automatic computation of the final mark and the appropriate grade (which I have not included in this exercise)

The conditions are accumulative rather than optional, and so the formula must be based on the AND operator rather than the OR operator.

E.g. if a>b AND c>d AND e>f ... is TRUE, then do something, and if FALSE, a default option is invoked.



The format of the IF statement isif ((argument), (action if TRUE), (action if FALSE))The next few commands will illustrate the ‘building’ of the

complex command in cell A70:

IF(AND(A66=0,A65=0),0,IF(AND(A67=1,A65=0),10,A68)) * * *

This covers the condition that the Practical Work Marks were

0,and the Exam Marks were 0, to give a result of 0, and the case where the Prac Work Marks were 0 and the Exam marks were >0 (result 10) and the default if these conditions were not present which is the normal Total Marks (A68)



So what we have is the ability to extend the conditions, and therefore the means of building a complex IF command (also known as nested IF’s)

Without going through all of the build manoeuvres, the final command looks like:

IF(AND(A66=0,A65=0),0,IF(AND(A67=1,A65=0),10,IF(AND(A67=1,A66>0,A65>A66)A66+10,IF(AND(A67=1,A66=0)10,IF(AND(A67=1,A66>0,A66>A65),A66+10,A70)))));

An extension is to include the case where for instance the Prac Works marks are 55 and the Exam Marks are 90.


More Information

Tutorials are in LaboratoriesB 3.42 B 3.42BB 3.43 B 3.45

and B 3.46

They run from 1.30pm to 3.00pm and are on 22/11, 23/11, 24/11 and 25/11 29/11, 30/11, 1/12 and 2/12 6/12, 7/12 and 8/12/2005

The examination is on Friday 10th December. It will start at 9.30m.


Be careful

Test extensively before putting into production use


Tomorrow

• We’re off to have a deeper look at Windows NT / 2000 / XP

• and some chips and buses

And if you saw a headline ‘Eye Drops Off Shelf ’ what would you think ?

cse1720 summer 2005 lecture 03 /1 lecture no. 3 software systems, memory management throughput,...

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