isys 101lecture #21 intro to information systems i system & application software isys 101 glenn...

ISYS 101 Lecture #2 1

Intro to Information Systems ISystem & Application Software

ISYS 101

Glenn Booker


System Software

• System software includes the operating system (OS) and utilities

• The operating system performs the basic functions for a computer to be a computer– Communicate between software and hardware– Read from and write to storage– Manage memory– Run applications


Operating System

• The main part of the operating system is the kernel, which is always in memory (“resident”) when the computer’s running

• Other parts of the operating system are called upon as needed (“non-resident”)

• Operating systems are CPU-specific– You can’t run Windows on a G4 processor


Operating System

• DOS was a single tasking operating system – you could only run one program at a time

• Most OS’s are multitasking – they can run many programs at once– One is the foreground application, the others

are background applications


Multitasking

• Older OS’s (Windows 3.1) used cooperative multitasking – the foreground application uses all of the CPU’s attention

• Newer OS’s (MacOS 8-X, Win NT) use preemptive multitasking, which isolates each application in memory– Even if an application crashes, the operating

system doesn’t


Multithreading, Multiprocessing

• Within one application, multithreading allows several tasks (“threads”) to be done at the same time– Most modern OS’s use multithreading

• Multiprocessing (MP) is when the computer has more than one CPU – For symmetric MP, each thread can be assigned

to a different CPU


Memory Management

• Memory (RAM) is divided into partitions for each application

• If RAM is limited, part of the hard drive can become virtual memory

• Chunks of memory are divided into “pages” to pass in and out of virtual memory

• Pages are written in a swap file on hard disk


Interfaces

• Hardware interfaces are controlled by programs called device drivers– Most are installed automatically

• User interfaces are– Command line (DOS, UNIX)– Menu-driven (CMOS – see later)– Graphical user interface (MacOS, Windows)


User Interface

• The user interface lets the user– Gain access to the computer (log in)– Run applications– Manage disks and files– Shut down the computer safely (necessary

since DOS)


Types of Operating Systems

• UNIX is a 30+ year old family of operating systems

• Mostly used for servers and workstations

• Dependable and very powerful, but hard to learn and somewhat obtuse (rename = mv)

• Two major subfamilies: IBM System V and Berkeley BSD


Major UNIX Brands

IBM AIX Sun Solaris, SunOS

Apple MacOS X SGI Irix

HP HP/UX DEC/ Compaq

Tru64 UNIX

On Intel-based computers, SCO and BSD are also available.



• MS-DOS powered the IBM PC in 1981, and is still partially the basis for Windows ME– Command line interface

– Copied by PC-DOS, DR-DOS

– 640 kB RAM limit originally

• While Xerox invented the GUI in the late 70’s, Apple capitalized on it with the Macintosh, now running MacOS 9 or X– 32-bit System 7 released in 1991



• Microsoft Windows– Windows 3.x added GUI on top of DOS,

but treated CPU as though it were 16-bit– Windows 95, 98, and ME are all still

DOS-based, but try hard to be 32-bit operating systems

– Windows NT and 2000 are clean 32-bit OS’s, which emulate DOS if needed



• Windows CE (WinCE?) is used for small portable devices (palmtops) (Windows lite)

• Linux is a clone of UNIX, developed starting in 1991 by Linus Torvalds– A third of Web servers run Linux– New GUI’s (Gnome and KDE) help reach

desktop market



• Mainframe or minicomputer operating systems include Unix and:– IBM’s OS/390 for S/390 computers– IBM’s OS/400 for AS/400’s– Compaq’s VMS for VAX/VMS or

OpenVMS-based computers



• Windows XP (“Whistler”) will be first Windows operating system for home and office which is 32-bit clean– It’s about time!– A special 64-bit version will be made for

Itanium

• BeOS (www.be.com) is a free OS for graphic and multimedia applications


Computer Startup

• Starting a computer is “booting” it– From turned off, it’s a “cold boot”– From already running, it’s a “warm boot”

• First see the BIOS (Basic Input/Output System) screen– BIOS controls what the computer boots from

(floppy, hard drive, CD) and helps initially configure the hard drives


Computer Startup

• After the BIOS is happy, the Power On Self Test (POST) makes sure the hardware is attached – Checks RAM, hard drive, floppy, keyboard,

and mouse

• Then the OS loads into RAM

• Then you can log in


Profiles

• If your OS supports multiple logins, then when you log in you get:– Unique desktop appearance as defined in your

user profile– A home directory for your files– Varying privileges for running applications


Utilities: File Management

• Basic file management utilities (like Windows Explorer) help organize files

• Files under Windows have a file name (myfile), a period, and extension (doc)– The extension is used to associate files with the

application used to open them

• Files are kept in directories (folders)


Utilities: Backup

• Backup utilities help archive the contents of your hard drive(s) in case of disaster or severe corruption of the disk

• Full backup copies everything in the disk (or specified folders)

• Incremental backup copies only those files which changed since the last backup


Utilities: File Compression

• File compression utilities squash files and directories to make backup or transfer (e.g. via floppy or email) easier

• WinZip and StuffIt are the most common

• Pkzip was an early DOS/Windows version

• Text files and bitmaps compress the best; some formats are already compressed (JPG)


Utilities: Disk Scanning & Defragmenting

• Some utilities help manage the physical hard drives, including defragmenting

• They also scan, erase, and format drives– Windows has built-in “scandisk” & defrag tools– DiskKeeper is used for Windows NT or 2000– FWB Hard Disk Toolkit for Mac


Application Software

• Application software is broken into horizontal and vertical apps– Horizontal apps are widely used across many

types of work (Word, Excel, etc.)– Vertical apps are designed to manage one entire

business function (e.g. manufacturing)

• Custom software is needed if one of the above doesn’t meet your needs ($$$$)


Application Software Types

• Three major categories of horizontal apps used for business– Personal productivity (Office)– Multimedia & graphics (Photoshop, Fireworks,

Paint Shop Pro, PageMaker, Quark)– Internet (Outlook, FrontPage, Internet Explorer,

Netscape)– Plus personal finance & tax software for home


Software Requirements

• The required hardware and software for running an application typically includes– Type of CPU– Type of operating system– Amount of RAM– Amount of hard drive space free– Other special needs (mouse, CD-ROM, etc.)


Software Licensing

• Commercial software is often charged per copy of the software, or per CPU

• Shareware is free, but you should send in money if you use it a lot

• Freeware is free

• Some software is public domain


Software Licensing

• Linux falls under the GNU Public License (GPL)

• Some demos or beta versions are time or feature-limited

• Academic software might have time or feature limits

• Site licenses help manage large facilities


Software Distribution

• Software may be distributed on CD-ROM or downloaded via the Internet

• Documentation may be electronic (PDF) and/or paper

• Versions (3.0) indicate a major revision;

• Maintenance releases (3.1) indicate minor improvements and fixes


Software Installation

• Software is installed using a special program for that purpose

• Installers uncompress files, and copy them to your hard drive

• Windows apps add entries in the Registry, and in the Control Panel called Add/Remove Programs


Software Installation

• Registration of the software is expected immediately after installation

• Some apps come with uninstall programs, too – otherwise use Add/Remove Programs to delete them (please!)


Visual Metaphors

• Good software is based on familiar visual appearances– Word processing looks like a letter– Spreadsheet looks like that used by an

accountant– Databases look like file cards– Contact managers look like an address book– Personal finance program looks like checkbook


Integrated Applications

• Often applications from a single vendor are integrated to work more closely with each other– MS Office, Works– Lotus SmartSuite, Corel Office

• On a larger scale, this leads to vertical applications (e.g. SAP)


Windows Environment

• A typical window has:

• Title bar at the top, with minimize, maximize, and close window controls on the right of the title bar

• Then a Menu bar (File, Edit, …)

• Then one or more Toolbars

• Your work is in the Application workspace


Windows Environment

• The right side of the window has the scroll bars, arrows, and boxes

• Under the workspace is the status bar (which tells you when you’re printing, etc.)


Word Processing

• Word processing allows composition of letters, reports, and other major documents with few formatting needs– If you need complex formatting, use a desktop

publishing program instead

• Basic word processing allows for creating, editing, formatting, and printing a document


Word Processing

• One document might be broken into Sections– Each section can have its own margins,

orientation (landscape vs portrait), page numbering, headers and footers

• Within a section, the paragraph is the next major element


Word Processing

– Each paragraph may have styles associated with it, as well as line spacing, indenting, and spacing before and after the paragraph

• Below the paragraph, the character is the next unit– Each character may have a font size, style,

color, and other effects (shimmer, etc.)– Symbols and images are characters


Word Processing

• Word processing programs can add other features, like:– Footnotes and endnotes, page numbers, tables

of contents, indexes, etc.– Tracking changes for document review

• Beware of grammar and spelling checkers!– Many errors won’t be caught be them


Spreadsheets

• Spreadsheets mimic an account’s spreadsheet – used to add rows and columns of numbers

• Now they also do charts and help analyze data

• Data are in columns (for each type of data) and rows (for each record or transaction)


Spreadsheets

• Excel limited to 256 columns and 65,536 (64k) rows

• One spreadsheet document can have many “sheets” (up to available memory)

• Spreadsheets calculate based on cell name references = A1 + B3*C3


Spreadsheets

• Spreadsheets recognize three types of data– Numbers (including percent, integers, real

numbers)– Dates and/or times– Text (“Hi this is a text cell”)

• Fill handles or autofill help enter patterns of data quickly


Spreadsheets

• Fixed, or absolute cell references can be defined = $A$1 + B3*C3 (fixes A1)

• Math functions can be used (beware of weak statistical functions) = SUM(B1:G1)

• Formatting of fonts, rows, columns, page breaks, etc. can be done too


Spreadsheets

• Most charts can be generated using the Chart Wizard– Also can embed Excel objects, including data

and charts, in a Word document

• Macros can be used for more complex programming in Excel

• Be sure to check sample calculations!


Presentations

• Presentation graphics (PowerPoint) are generally for less technical work than analytical graphics (Excel or SPSS)

• Images are based on vu-graph slides

• Slides can be viewed together (slide sorter), or view an outline of the presentation

• The Notes view reminds you what to say


Presentations

• A master slide can contain common elements you want in the background for every slide (logos, copyright data, presentation or presenter name, etc.)

• Now presentations can have headers and footers too, like Word documents

This stuff is in the footer!


Presentations

• Templates can provide a set of predefined layouts and fonts, but generally do so at the expense of contrast (use a good projector!)

• Entire presentations are outlined in the AutoContent Wizard (under File / New)

• Animation and movement can also be used

• But sometimes badly


Presentations

• Sound, video, and Internet content are possible

• Keep the content focused on each slide

• Some recommend no more than five lines, with 5 words per line (the 5x5 rule)

• Fonts generally shouldn’t go below 24 point

• This is 32 point Times, with 44 point titles


Databases

• Databases are used for storing, sorting, and analyzing lots of data

• Data is stored in tables

• Forms are used for displaying and entering data

• Reports are used for output of data

• Queries are used to select data from tables


Database Tables

• Tables have records; records are like rows in Excel

• Each record (customer) has one or more fields in it (name, address, zip code); fields are like columns in Excel

• Each field has a data type (text, number (integer or real), money, date, T/F, etc.)


Databases

• Each table is one type of information which can be associated with one unique identifier– A person has a SSN– A purchase order has a PO number

• That unique identifier is the “primary key”

• One event (a purchase) may involve data from several different tables


Databases

• For example, one customer may have placed many orders

• A single order may have many items in it

• But a customer might have only one shipping address

• Those one-to-many and one-to-one relationships make a relational database


Databases

• The use of relational data prevents duplication of data, and allows analysis in many ways otherwise not possible

• Reports can be generated which draw from many tables

• Forms may accept input which goes into several tables


Databases

• Queries draw from many tables to find, for example, a particular type of data, e.g.– Find all of the customers in the Delaware valley– Determine the total sales for each sales person

last month– Which suppliers have been most reliable?– When do we need to reorder tuna fish?


Other Database Considerations

• Validation: databases can check their inputs and outputs to make sure they are the correct format and range

• Data integrity refers to data being a correct possible value (gender = M or F, not Q)

• Database independence refers to the ability to keep the data when the database program needs to be updated or replaced



• Data should be kept in only one place (no redundancy)

• Data needs to be secure, so that only those who need to get to it may do so

• Maintenance issues need to be addressed, such as adding or deleting data or users of the database



• Large scale databases need to consider the need for replication, where several copies of data are maintained in different servers– Local replication is also done (e.g. sales staff

maintaining a replica of product features and costs)

• The location where computation is done may be distributed to different servers


Other Database Types

• A flat file database is like using multiple spreadsheets (FileMaker Pro, or COBOL)

• Object-oriented databases exist; some are cross-bred with relational databases to make object-relational databases

• Groups of databases can form warehouses or data marts, and support data mining


Database Architecture

• Databases can be client/server architecture (users run a client program, which asks the server for data as needed)

• Or many databases are becoming web-based (typically using CGI, ASP (Microsoft), or JSP (Sun) programs to query the database)

isys 101lecture #21 intro to information systems i system & application software isys 101 glenn...

Documents

dos slide

windows slide

doesnt slide

hard disk slide

different cpu slide

berkeley bsd slide

memory run applications

glenn booker slide