An Overview of the PC PC and DOS Essentials

The Components of a PC The Key Year –The IBM PC –The Intel 8086 –DOS All versions of these items have been obsessed with backwards compatibility ever since!

The Operating System DOS and Windows DOS, the operating system acts as a link between your PC hardware and your applications Windows 3.x is a further layer built on top of DOS Windows 95 is to a large extent independent of DOS WINDOWS DOS HARDWARE

Storage Devices Floppy disks (diskettes) –Slow but convenient –Hold only small amounts of data (1.44 MB) Hard disks –Fast –Relatively cheap –Hold large amounts of data Tape drives –Excellent for back-ups CD-ROMs –Excellent for storing data as reference material –A convenient method for installing programs, such as Microsoft Office

The Serial and Parallel Ports Parallel communication –Faster than serial communication –Used to connect the PC to a printer Serial communication –Slower, used for connection to a modem

The CPU (Central Processing Unit) The CPU is responsible for all calculations performed within the PC It determines how fast the PC will run and what systems will run on it Additionally, it gets involved in a host of other activities, such as overseeing the transfer of data from the hard disk into RAM

The ROM-BIOS and the CMOS-RAM The ROM-BIOS –Read Only Memory - Basic Input Output System –Interface between DOS and the PC hardware The CMOS-RAM –Complementary Metal Oxide - Random Access Memory –A read/write chip –Stores the system configuration, time and date as well as the power-on password (if you have set one)

PC Interrupts 16 hardware interrupts Allows items within the PC to signal to the CPU that they require attention Items must not use the same interrupt line Use the MSD command to view interrupt usage When a new card is installed into a PC you must ensure that it does not try to use an interrupt that is already in use

DMA (Direct Memory Access) DMA was introduced in 1981 with the release of the IBM PC –VERY SLOW! The original PC was based on the Intel 8086 CPU, which at the time was considered an OK sort of chip, running at a reasonable speed –To help out the CPU, the DMA was responsible for moving information from the hard disk or floppy disk into memory, thus by-passing the CPU. This increased throughput and performance

Types of Bus Architecture ISA (Industry Standard Architecture) is the original PC bus architecture, introduced in 1981 MCA (Microchannel Architecture) was introduced by IBM in 1987 and eliminated many of the ISA design bottlenecks EISA (Extended Industry Standard Architecture) was introduced in 1989 Plug and Play is the latest solution and allows automatic hardware configuration

‘Plug and Play’ Provides a mechanism for automatically configuring any items you add to your PC Requires three elements to work successfully –The operating system must be Plug and Play aware Windows 3.1 is not Plug and Play aware, Windows 95 is –The ROM-BIOS must be Plug and Play aware –The cards themselves must be specially designed to be Plug and Play aware

Getting HELP Within DOS and Windows Help in DOS is limited –HELP –command /? –HELP command Most Windows applications (and Windows itself) contain tutorials, which are very useful for new users –As later versions of applications are released, the Help files are often modified to give improved information concerning tips and tricks –Context-sensitive Help should be invoked when F1 is pressed

Directories and Files PC and DOS Essentials

What are Directories? A convenient way of dividing up your hard disk Each application can be kept in it’s own directory –The root directory is called CD\ –A single. represents the current directory –A double.. represents the parent directory

Manipulating Directories Under DOS Directory commands include: MD CD RD TREE DELTREE Please take care using DELTREE

Manipulating Directories Using the Windows File Manager Run the File Manager program, by double clicking on the File Manager program icon, located within the Main group

The DIR Command Switches include: –/w –/p –/s –/?

What are Files? A file is a collection of information contained in a single unit, stored on disk The DIR command displays a list of files contained in the current directory (the current directory is the directory you are in at the time)

File Naming Conventions There are very strict rules governing the naming of files A file name can be up to 8 characters, with a 3 character file extension. You cannot use spaces (produced by pressing the spacebar) within a file name File names, must not contain the following characters:- \ | * ? + You can use the underscore character –This is often useful for making a file name more readable. You can use numbers as well as letters

Internal vs External DOS Files External DOS files are held on the disk, and loaded into your computers memory (RAM) only as and when required Internal commands are pre-loaded in your computers memory (RAM) when you switch on a DOS-based computer

Creating Text Files - EDIT vs COPY CON COPY CON is a useful technique for creating small text files Edit is useful for editing existing files or creating large complex text files

Renaming, Deleting and Undeleting Files DEL –Deletes files REN –Renames files UNDELETE –Undeletes deleted files Give me my files back! Beware of accidental file deletion!

Copying and Moving Files Under DOS COPY –Internal command –Copies files XCOPY –External command –More flexible than copy MOVE –External command –Only works within a disk, not between disks Everything well organized!

Copying and Moving Files Using the Windows File Manager Open the File Manager Click on the File drop-down menu Select the Copy or Move command

Viewing and Finding Files Within DOS View with the TYPE command Use DIR/s to find

Viewing and Finding Files Using the Windows File Manager Open the File Manager Click on the File drop down menu Select the Search command Double click on an associated file to view the file Associated files

Manipulating File Attributes Attributes –Read Only –Archive –System –Hidden Use of ATTRIB –RRead-only –AArchive –SSystem –HHidden In Windows manipulated via the File Manager –File/Properties

Disk Fundamentals PC and DOS Essentials

Types - Floppy Disks (Diskettes) and Hard Disks Hard disks –Non-removable –Inside your PC –Very fast –Hold large amounts of data Diskettes –Removable –Hold up to 1.44 MB –Very slow

Setting Up a Hard Disk From Scratch Low level formatting –Hard disk supplied with low level formatting –DOS FORMAT command will not low level format a hard disk Partitioning –With FDISK High level formatting –Using DOS FORMAT command

Disk Partitions Options include setting up: –A single primary partition –A single extended partition –Multiple logical drives Manipulated via the DOS command FDISK –A logical drive is anything addressed by a drive letter –If you have a single large primary partition, it is referred to as drive C: –If you have an extended partition, use FDISK to split this into one or more logical drives –Referred to as drive D: E: F: etc.

High Level (Logical) Formatting Also called logical formatting All logical drives within hard disk partitions must first be formatted Use the DOS FORMAT command Only drive C: needs to be a system (bootable) disk

Diskette Formatting Considerations System and non-system diskettes Quick formatting Non-System Disk! ?

Unformatting a Disk UNFORMAT When you format a disk, by default it saves information concerning the disks contents Providing that you use the UNFORMAT command immediately this information can be used to restore the contents of the disk

Copying and Labelling Diskettes DISKCOPY –Uses identical source and target diskettes

Speeding Up Disk Access With DEFRAG Removes file fragmentation Speeds up disk access Run DEFRAG if the disk appears slow The effect can sometimes be dramatic

Buffers Used to speed up access from the disk Set up via the CONFIG.SYS

SmartDrive Setup via the AUTOEXEC.BAT Can increase to AND from the hard disk

Disk Compression DBLSPACE and DRVSPACE Compresses data held on a disk, and increases the storage capacity Is it safe? What about disk performance? Before After

Disk Structures Sides Sectors Tracks Clusters

The DOS Boot Sequence The boot record Two hidden system files CONFIG.SYS COMMAND.COM AUTOEXEC.BAT

RAM Disks You can treat part of your memory (RAM) as a virtual disk Accessed much faster than a real disk Useful with Windows, as you can create temporary files of a virtual disk (by pointing the TEMP= variable to the virtual disk, within the AUTOEXEC.BAT)

Memory Fundamentals PC and DOS Essentials

Type of Memory Chips - RAM and ROM RAM –Random Access Memory –Read/write memory –DOS and application programs are loaded into RAM ROM –Read Only Memory –Contains hard coded information that is used by the operating system –ROM-BIOS –Video ROM –Hard disk ROM

The IBM PC, the 8086 CPU and DOS The original IBM PC containing an Intel 8086 CPU and DOS were all released at the same time The original PC was designed around the Intel 8086 CPU and DOS in turn was designed to run specifically on the 8086 CPU DOS has since been left behind by the hardware, including the CPUs It’s not 1981 anymore! DOS

Conventional Memory Defined by addressing limitations of the 8086/8088 CPU Is the first 1 MB of memory Not protected Traditionally only 640 KB used by DOS and DOS applications

Extended Memory Protected Memory above 1 MB –Used by Windows and Windows applications –The original CPU for which DOS was designed only had 20 address lines, and could only address a maximum of 1 MB –In 1984, with the release of the IBM AT based on the Intel CPU, the number of address lines was raised to 24, giving a maximum memory address range of 16 MB –The first 1 MB was addressed in Real Mode, while the remaining 15 MB were addressed in Protected Mode and were referred to as Extended Memory –386/486-based PCs can, in theory, address 4 GB of memory Extended Memory Specification - (XMS) –Defines a standard used to access Extended Memory –DOS and Windows use a driver HIMEM.SYS to control access to the XMS memory

Expanded Memory An Old Technology! Used only by certain DOS applications –Windows applications do not require Expanded Memory –Used to extend the life of old 8086-based PCs (which could only address 1 MB of Conventional Memory) –Modern DOS programs will tend to use Extended Memory rather than Expanded Memory –Traditionally requires a special Expanded Memory card and a special device driver –Requires a 64 KB page frame in the UMBs May now be emulated from Extended Memory by using the EMM386.EXE device driver DEVICE=C:\DOS\EMM386.EXE

The Upper Memory Blocks and the High Memory Area The UMB space is located between 640 KB and 1 MB The HMA is a 64 KB area just above 1 MB Conventional Memory UMBs HMA 0 KB 640 KB 1 MB

Using the UMBs and HMA - Devicehigh and Loadhigh Allows you to load items with the CONFIG.SYS and the AUTOEXEC.BAT above the 640 KB limit CONFIG.SYS –DEVICE=C:\DOS\HIMEM.SYS –DEVICE=C:\DOS\EMM386.EXE –DOS=HIGH,UMB –DEVICEHIGH..... AUTOEXEC.BAT –LH.....

Virtual Memory - Used by Windows! Treats part of your disk as if it were memory –Used by Windows and Windows applications, but not by DOS –Transparent to Windows applications –Only used when physical memory is full –DOS was designed for the Intel 8086 CPU, which did not support Virtual Memory. Consequently, DOS does not support Virtual Memory –Virtual Memory is used by Windows 3.1 which was designed to run on 286 and 386 CPUs (which do support Virtual Memory)

Examining Memory Use the MEM or MSD commands System Info is available via the Help drop-down menu of most modern Microsoft applications

Configuring Your PC PC and DOS Essentials

The DOS Boot Sequence ROM-based diagnostics run first Then the Boot Record is executed IO.SYS loads MS-DOS.SYS loads If a CONFIG.SYS is present, this is then loaded COMMAND.COM is then loaded Lastly, if present, the AUTOEXEC.BAT is loaded

Conditional Booting To completely by-pass the DOS configuration First either boot or re-boot the computer When you see the message ‘Starting MS-DOS’... –Either depress (and release) the F5 key –or depress (and keep depressed) the Shift key

The CONFIG.SYS The CONFIG.SYS file is optional and is used to customize the way your PC will work –For instance, it may be used to set up the country characteristics for countries other than the United States (DOS is basically American and needs customization for proper use outside the USA) Device drivers are software that extend the function of DOS in a particular way –For instance, if you have installed a particular tape drive, you may need to install a tape device driver (supplied by the tape manufacturer) that instructs DOS on how to talk to the tape drive unit

The AUTOEXEC.BAT A batch file that executes automatically when you boot the PC Sets items such as the PROMPT and PATH OFF PROMPT $p$g PATH C:\WINDOWS;C:\DOS SET TEMP=C:\temp MODE CON CODEPAGE PREPARE=((437) C:\DOS\EGA.CPI) MODE CON CODEPAGE SELECT=437 KEYB UK,,C:\DOS\KEYBOARD.SYS

The DOS PATH The PATH command is normally set from within the AUTOEXEC.BAT Defines a search path for executable files or batch files (i.e. files that run when you type in the correct file name and press the Return key) –It is important to remember that by default DOS always searches the current directory first (i.e. the directory you are in when you issue a command) –The root directory of a disk will only be searched if it is the current directory, or if it is specified in the PATH statement –Held as an environment variable, within the DOS environment A small area of memory used for storing variables for use by DOS, Windows or other applications

The DOS Environment The DOS Environment is a small area of memory used by DOS, Windows and some other applications to store used items of information Standard items include the Path, Prompt and COMSPEC variables Windows uses the TEMP= variable to determine where to store temporary files Use the SET command to view the contents of the Environment

‘Loading High’ Since the release of DOS 5 elements of DOS may be loaded above 640 KB CONFIG.SYS –Use the DEVICEHIGH statement AUTOEXEC.BAT –Use the LH statement Allows you to free up Conventional Memory for use by DOS application programs

Configuring a Windows-Based PC Most Windows configuration is set via the Control Panel

Batch Files, I/O and Redirection PC and DOS Essentials

What are Batch Files? Batch files allow you to assign repetitive tasks to a small file which once created may be run as often as you wish Batch files have a.BAT file extension The AUTOEXEC.BAT is a batch file with the special property that it will run automatically each time you boot DOS

REM and ECHO REM –This allows you to document a batch file –Not displayed on the screen REM message ECHO –May be used to turn off echoing of batch file statements ECHO OFF –ECHO OFF often preceded which turns echoing off for the line containing OFF –May be used to display (echo) messages to the screen ECHO message –May be used in batch files to activate the system bleep ECHO ^G (CONTROL+G)

GOTO and CALL GOTO –Allows you to go from one line to another, within the same batch file –A single trip (no automatic return) –You go to a label which is indicated by a preceeding colon (:) :START TYPE C:\AUTOEXEC.BAT PAUSE GOTO START CALL –Used to transfer control from one batch file to another batch file –When the second batch file has finished processing, control automatically returns to the original batch file

PAUSE Used to temporarily suspend batch file processing By default displays a message ‘Press any key to continue’

I/O, Device Names and Redirection Standard devices include: –The console –The serial port –The parallel port –The console –The NUL device Standard Output –Informational output that is displayed on the console (screen) by default –May be re-directed to the NUL device Standard Error –Information concerning errors that is displayed on the console –Cannot be re-directed to the NUL device TYPE AUTOEXEC.BAT > LPT1: XCOPY A:\ C:\ > NUL

Piping The output of one command is fed directly into a second command, and will modify the output, which is then displayed on the standard device (i.e. the screen) Used by certain DOS commands –MORE –FIND –REPLACE TYPE C:\WINDOWS\WIN.INI ¦ MORE The output is modified so that it is displayed one screen at a time

Advanced Batch File Concepts PC and DOS Essentials

What are Variables? A variable is like a container such as a cup –The cup is always called a cup, but the contents of the cup can change –For instance the cup may contain coffee or tea –But the container is still called CUP –DOS can use this idea of a named container, i.e. variable The DOS path is held in a container called PATH, it is always called Path, but as we know the contents of the Path may be changed PATH C:\DOS C:\DOS;C:\WINDOWS OR

Command Line Parameter Substitution This concept allows you to run the batch file and specify parameters that are picked up by the batch file and used within it –Each parameter is separated by a space BATCH_FILE Parameter1 Parameter2 Parameter3...

Environment Variable Substitution The DOS environment is a small area of memory used for storing variables Environment variables include: –PATH, PROMPT, TEMP, COMSPEC To set an Environment variable use the syntax: –SET variable= value To put an Environment variable into a batch file use: –%enviroment_variable_name% To add an Environment variable to the DOS path, use: –PATH=%PATH%;%1 –NB: This assumes that the existing path does not end with a semi- colon (;)

IF EXIST Used to detect the existence of a particular file NOTE that this command will NOT detect the existence of a directory IF EXIST C:\AUTOEXEC.BAT GOTO DONTCOPY : DONTCOPY

IF ERRORLEVEL Some DOS commands issue ERRORLEVEL reports on completion Also called return codes or exit codes –An Error level of 0 normally indicates success –An Error level above 1 normally indicates failure IF ERRORLEVEL 3 GOTO SOMTHING_WRONG_3 IF ERRORLEVEL 2 GOTO SOMTHING_WRONG_2 IF ERRORLEVEL 1 GOTO SOMTHING_WRONG_1 IF ERRORLEVEL 0 GOTO NO_PROBLEM ERRORLEVEL is supported by: BACKUPCHKDSK CHOICEDEFRAG DELTREEDISKCOMP DISKCOPYFIND FORMATGRAFTABL KEYBMOVE MSAVREPLACE RESTORESETVER XCOPY

DOSKEY Macros Use DOSKEY to create them DOSKEY TA TYPE C:\AUTOEXEC.BAT Similar to DOS-based batch files BUT held in memory, not on the disk Faster than Batch files Volatile Load via the AUTOEXEC.BAT if you want to make them more permanent

Printers PC and DOS Essentials

Types of Laser Printer PCL vs Postscript PCL (Printer Control Language) –Not so good for DTP –Device dependent –Reasonably fast –PCL5 used in HP LaserJet 4 series –Normally used with resolution enhancement Postscript –Much more flexible and configurable –Slower –More expensive hardware required –Ideal for graphics and DTP –Device resolution dependent

Printer Considerations Important items to consider when specifying a printer are: –Speed –Resolution –Resolution Image Enhancement –Printer memory –Duplex printing

Printer Drivers for DOS and Windows Each DOS program requires its own printer driver All Windows programs use a single Windows printer driver PRINTER DRIVER

Security, Backups and Viruses PC and DOS Essentials

What are Viruses? Viruses can cause permanent loss of data Viruses spread from one PC to another, even across networks ALWAYS use a virus checker on your disks Suddenly, I do not feel so well!

Virus Protection Methods DOS and Windows MSAV –Run from the command line or from the AUTOEXEC.BAT VSAFE –TSR program –Constantly on alert for viruses Windows 3.1 is given anti-virus tools by DOS

Backups Under DOS –Use MSBACKUP In Windows –Open the File Manager and click on the Backup command, located under the Tools drop down menu Perform REGULAR backups!

Fixing Errors On a Disk Disks are physical devices, and disk drives are full of moving parts Like anything else, they are prone to wear and tear as they get older CHKDSK /F and SCANDISK can be used to fix a range of problems that may occur on your disks Use SCANDISK rather than CHKDSK it is safer and more effective

Windows Fundamentals PC and DOS Essentials

The Advantages of Using Windows The Microsoft sales pitch –Multitasking –Uses all available memory –Has a consistent User Interface –Allows programs to talk to each other The down side –Prone to crashing –Does not multitask in a sensible way

Select, then Manipulate! The basic rule when using Windows!

Components of a Window The Title Bar The Menu Bar Borders

Maximizing, Minimizing and Restoring a Window Maximize –Causes the program to fill the whole screen Minimize –Causes the program to be displayed as an icon Restore –Restores an icon to a window, or a full screen program to a window

Moving and Re-sizing a Window Any program displayed as a window within Microsoft Windows can be moved around on the screen Any program displayed as a window within Microsoft Windows can be re-sized either horizontally, vertically, or in two dimensions at the same time

Menus and Dialog Boxes All windows programs have drop down menus of one sort or another. The drop down menus within a Windows program allow you to interact with a program. For instance, most applications have a File drop down menu containing commands such as Open, Save, or Exit

Multitasking Within Windows When you multitask programs under Windows on your PC, they appear to run simultaneously –In fact each program is allocated a small proportion of the CPUs attention and whilst one program is running, the other programs are temporarily suspended –By default, all Windows applications will appear to run simultaneously, whilst DOS programs will only run when in the foreground

Using the Task List Displayed in a window and, as the name suggests, lists all the tasks (i.e. programs) that are currently running in memory Allows you to easily switch to any of the programs listed in it, or to close any program listed in it Can tile or cascade programs –This causes each separate program that is running to be displayed either side-by-side, or in a layered fashion You can arrange the icons at the bottom of the screen

The Program Manager, File Manager and Control Panel PC and DOS Essentials

Program Manager Groups A number of standard groups are installed by default –Main group –Accessories group –Games group –StartUp group Groups can be added, deleted or modified

Manipulating Groups and Adding Programs Click on File and select New This dialog box is displayed when you create a new program group or program item

File Manager Terminology It is important to understand the terminology associated with using the File Manager

Directories and Drives Make sure that you know how: –To expand a directory level –To expand all directory levels –To indicate expandable branches –To collapse a directory level –To display a particular directory –To change the active disk drive

The Control Panel Allows you configure items including: –Colors and Fonts –Ports –Mouse and Keyboard –Desktop –Printers –International settings –Date/Time –Sound and Drivers –386 Enhanced