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Chapter 2. Special Terms and Features in X-DOS This chapter will familiarize you with the terminology used in this manual and introduce you to the basic rules of DOS usage. Most of the terms used are standard throughout the computer industry, but if you have not previously worked with computers, many of the terms in this manual will be new to you. Users that are already acquainted with other disk operating systems for personal computers should at least browse through this chapter since it contains information that is unique to X-DOS 5.0. The Command Line Whenever you want to issue a X-DOS command or want to run an application program, you will have to be at the command line. The command line is also referred to as the X-DOS prompt, since you will always be prompted for input at the command line. The X-DOS prompt can easily be customized by the user with the PROMPT command but the default X-DOS 5.0 prompt appears like this: A:\DOS| where A: shows the default disk drive , \DOS shows the default directory (i.e. path) and | is the prompt delimiter. The path is shown above the line where you will enter your commands. Whenever you see the X-DOS prompt, this means that X-DOS is waiting for you to enter a command, which can be any X-DOS command or a command to load an application program. To run a command, you must type the name of the command and press the [Enter] key on your keyboard. X-DOS will then try to carry out the command you have entered. You must always press the [Enter] key on your keyboard following the name of the command to carry out any command. Files and Filenames To keep track of data, X-DOS stores the data in a file on a disk(ette) just like a folder in a drawer of a filing cabinet. Files can contain any kind of information from normal text to computer understandable information. To distinguish different files, they must all have a name. A filename consists of two parts: a name and an extension. The name usually describes the contents of a file while the extension is often used to specify the type of file. Here is an example of a filename: FILENAME.DOC 2-1 where FILENAME is the name of the file and .DOC is the extension. The filename and the extension together are often referred to as the filespec. You can enter a filename in either upper or lower- case since X-DOS does not distinguish case for filenames. The name part of a filename must always be present and it can consist of from one to eight characters. The extension is optional except for program files that must have an extension of either .EXE or .COM and .BAT extension. It is normally a good idea to include the extension as part of the filespec to describe the type of file, like .DOC or .TXT for text files. The extension can be up to three characters long and must always be preceded by a period (.). The following characters can be used in both the name part and the extension of X-DOS filespecs: * All letters in both upper and lower-case from A to Z * All digits from 0 to 9. * The following special characters: ! @ # $ % & ( ) - { } ' Even though X-DOS lets you use special characters in filenames, you should normally try to avoid using these characters unless you have a good reason to do so. Directories To organize your files into groups of related files, X-DOS 5.0 lets you create directories. A directory is an area on a disk or diskette which contains information concerning the files related to that directory such as the filename, the file size, and the last modification date for each file. A directory can be compared to a drawer in a filing cabinet, containing folders of related data. If you do not use directories to organize your files, you will probably soon experience problems keeping track of your different files. There are also certain limitations to how many files you can store in the main directory of a disk, which is called the root directory. The root directory is automatically created when a disk(ette) is formatted and must always be present on a disk(ette). You can create directories in the root directory, you can create sub- directories in a directory of the root directory, and so on. Directories below the root directory are called sub-directories. You can create sub-directories many levels deep but you should try to keep the number of levels in your directory structure to as few levels of sub-directories as possible or it may otherwise be very difficult to keep an overview of your directory structure. 2-2 The naming convention of directories follows that of filenames. You can have a directory name of from one to eight characters and an optional directory extension of up to three characters. Extensions on directory names are seldom used since the name normally is enough to describe the contents of the directory. The directory you are currently residing in is called the default directory. You will have a default (current) directory for each of your drives. A directory one level above the default directory is called the parent directory and any sub-directories to the default directory are called child directories. When you display the contents of a directory you have to be able to distinguish between files and sub-directories in the directory you are displaying the contents of. When you display the contents of a directory other than the root directory you will probably notice that the directory seems to contain two directories which are named `.' and `..'. These two directory entries are available in all directories except for the root directory. The `.' entry is a substitution character for the default directory and the `..' entry is a substitution character for the parent directory. Here is an example on how you can use these substitution entries. Let us for a moment assume that your default directory is C:\PROGRAMS\WORDPROC and you want to display the contents of the C:\PROGRAMS directory with the DIR command. Normally, you will have to type: DIR C:\PROGRAMS Since the C:\PROGRAMS directory is the parent directory to the C:\PROGRAMS\WORDPROC directory you can save a lot of typing by using the parent substitution entry `..' instead of specifying the directory path. By doing so you can display the contents of the C:\PROGRAMS directory just by typing: DIR .. The Path The path in X-DOS is like a road map through directories, describing how to get to your files. PATH is an X-DOS command but is also used to describe a range of 2-3 successive directories to reach a specific file. Look at the following example. You have a file by the filename EXAMPLE.COM stored in a sub- directory of the root directory called PROGRAMS. If the default directory is the root directory then you can specify the road to the EXAMPLE.COM file like this: PROGRAMS\EXAMPLE.COM where PROGRAMS\ is the path to the file EXAMPLE.COM. Since EXAMPLE.COM is an executable file, you could type the above line followed by [Enter] to run the program. If you want to be able to reach EXAMPLE.COM from anywhere on the drive, you only have to precede the previous example with a backslash (\) like this: \PROGRAMS\EXAMPLE.COM This tells X-DOS to start looking for the PROGRAMS directory from the root (\) directory of the default drive, no matter what the default directory is. This can be expanded even further since you might not be on the same drive as the EXAMPLE.COM file. To reach the EXAMPLE.COM program from anywhere on your disk drives you should type: d:\PROGRAMS\EXAMPLE.COM where d: can be any valid drive specification, such as the A: drive. If the file EXAMPLE.COM resided in a sub-directory of a sub- directory, it could get rather tedious to execute the program since you would either have to be in the same directory as the file or you would have to issue a lengthy path along with the filename. To avoid this, X-DOS lets you specify a path with the PATH and ADDPATH commands. In this path, you can insert the route to the directories you want X-DOS to search through when you want to run a program. To avoid having to type a lengthy path every time you boot your computer, insert the PATH command with your preferred range of directory paths in the AUTOEXEC.BAT file. The AUTOEXEC.BAT file is a configuration file that is automatically executed every time you reboot your computer. You will probably want to include a path to all of the directories which contains executable files that you often use. If you temporarily want to append a path to a directory which is not normally included in your PATH statement, you can use the ADDPATH command to add this path to the end of your current path. 2-4 Memory You need Memory (also called RAM or Random Access Memory) in your computer to be able to run any kind of program. Whenever you want to issue an X-DOS command or run an application program, it must first be loaded into memory before your computer can execute it. Even when you boot your computer, X-DOS 5.0 takes up some memory by placing some of its system files permanently in your memory. There are different kinds of memory; conventional (base) memory, extended memory, and expanded memory. The conventional memory on a personal computer is the memory used by programs to execute from within and can be no larger than 640K. This is due to the design of the early versions of IBM's personal computers and limitations of the Intel 8088 microprocessor, the chosen microprocessor for these personal computers. Today many personal computers are shipped with more memory than 640K as a standard. The memory above 1MB is normally what is called extended memory. The third kind of memory, expanded memory, is often referred to as EMS or LIM memory. This kind of memory will let you run large programs that would otherwise not be able to run or would run inefficiently in conventional memory. To be able to use expanded memory with a program, the program must be specifically designed to take advantage of expanded memory. You will normally have to get a special memory expansion card to acquire this type of memory but more and more personal computers are shipped with utilities that allow you to transform extended memory into expanded memory such as the VRAM/386 program included in the Professional X-DOS diskette. The virtual disk manager (VDISK.SYS) in X-DOS lets you create a virtual disk in expanded memory or extended memory. Another kind of memory is ROM (Read Only Memory). All PCs have ROM and this usually contains the BIOS (Basic Input Output System) which is firmware that ensures your PC is compatible with the industry standard. The X-DOS operating system can also be stored in ROM depending on the design of the PC being used. File Types in X-DOS In this section you will learn about the different file and program types that X-DOS 5.0 uses and recognizes. The System Files 2-5 X-DOS 5.0 has three system files called X-DOS.SYS, ]COMMAND.COM, and MAX.COM. Two of these, X-DOS.SYS and COMMAND.COM, are essential for X-DOS and must always be present for X-DOS to work. The third system file, MAX.COM, is the second command processor and is not essential for running X-DOS 5.0, although the absence of this file greatly reduces the number of commands available in X-DOS. The X-DOS.SYS file must always be in the root directory of your boot drive. It is a Hidden file which means that you will not normally be able to see it when you list the contents of the root directory. COMMAND.COM and MAX.COM are Read-Only files which means that you will not be able to accidentally overwrite these files. Executable Files Any files with an extension of .COM, .EXE or .BAT are treated by X-DOS as executable files. You can always run an executable file by typing its name at the command line followed by pressing the [Enter] key. When you run a program, you do not need to type the extension since X-DOS automatically looks for a file with one of the three extensions above. All of X-DOS's external commands have an extension of .COM or .EXE as do all application programs. If you try to execute a file with a different extension than the three listed above, X- DOS will display an error message. The CONFIG.SYS File You can use the configuration file CONFIG.SYS to customize X-DOS to your needs. The CONFIG.SYS file is an ASCII text file and is used by the system files to install X-DOS during start-up according to the contents placed in it. If you have a CONFIG.SYS file, it must always be present in the root directory on your boot disk(ette) or X-DOS will not be able to find it. Device Drivers Excluding CONFIG.SYS, files ending with .SYS and sometimes .BIN are device drivers and are normally related to the hardware configuration of your computer. To install a device driver you must list it in the CONFIG.SYS file. Internal Commands Internal commands are X-DOS commands that are inside either one of the two command processors COMMAND.COM or MAX.COM. You will not be able to see an internal command if you list the contents of your disk(ette) but you can still execute them the same as executable files. 2-6 Since some internal commands are already in memory, they will execute very fast and you can call them from anywhere on your disk. X-DOS has more than 80 internal commands. DIR, CLS, CD, and MD are examples of internal commands. External Commands External commands are X-DOS commands located on your disk(ette) with either an extension of .EXE or .COM. It is important for you to make sure that X-DOS can find its external commands when you need them. As a default, X-DOS assumes that they are in a \DOS directory on your boot disk(ette). You can change this by using the PATH command to look for executable files in other directories. CHKDSK.COM, DEBUG.COM, FORMAT.COM, ED.EXE, and SETUP.COM are examples of external X-DOS commands. Batch Files Files with a .BAT file extension are batch files and are sometimes referred to as command scripts and are essentially plain text (ASCII) files. In batch files you can list any commands or programs you want to run, line by line, and X-DOS will process each line one at a time. This allows you to link a series of commands and programs to one filename. During boot-up X-DOS always looks for one specific batch file called AUTOEXEC.BAT which is executed if it exists. Insert any statements in this file that you want to run every time you boot your computer. Application Programs An application program refers to any program like a word processor, a database, a spreadsheet, and so on. As a guideline, application programs are often large programs consisting of multiple files. Wordstar and Lotus 1-2-3 are examples of application programs. Error Messages The X-DOS operating system uses error messages to tell you when it encounters a problem while processing a X-DOS command or any other program. Probably the most common error message you are going to see is: Specified filename invalid This error message tells you that X-DOS could not find the command or program name that you just tried to execute. You either typed it incorrectly or X-DOS was not able to find it on 2-7 the specified path. Another kind of error message requires that you take action before you can continue. An example is when you try to access a floppy drive without any diskette or with the floppy drive door open. In that case you will see the following error message: Fatal Error occurred on drive A Operation was : reading from drive A Error reported : Drive not ready, Disk area error : Dos area You can (A)bort, (R)etry, (F)ail ? External and Internal Storage Devices Since all of the information in your computer's memory is lost when you turn off your computer, you must have some kind of external storage medium to store your files onto. The most common external storage media are diskettes and hard disks. X-DOS references all drives on your computer with a drive letter. Two letters are reserved for floppy drives; drive A: and drive B:. Even if your computer only has one floppy drive, X-DOS still reserves the drive letter B: for a future floppy drive. Drives on your hard disk will therefore be designated with a drive letter beginning from drive C:. Drives can be referenced from drive A: to drive Z:. Virtual (RAM) disks are internal storage devices and are also referenced with drive letters, beginning with the designator after your last logical drive, if the virtual disk statement follows any partition manager statement you may have in your CONFIG.SYS configuration file. You can make any of the available drives the default (current) drive by typing the drive letter followed by a colon (:) and then pressing the [Enter] key. If your default drive is drive C: and you want to change to drive A:, at the command line you should type: A: Floppy Drives and Diskettes Virtually all personal computers have one or two floppy drives. You use floppy drives to store and retrieve data from diskettes. A diskette is a flexible plastic disk which stores the data magnetically. Diskettes come in many formats for personal computers, the most common of which are: 5 1/4" 360K diskettes, 3 1/2" 720K diskettes, 5 1/4" 1.2M diskettes and 3 1/2" 1.44M diskettes. 2-8 Hard Disks Hard disk drives are storage devices of large capacity, normally mounted inside of a computer. A standard 20M hard disk can store an amount of data equal to the contents of more than fifty-five 360K diskettes. A hard disk also retrieves and stores data many times faster than a floppy drive. These features make hard disks preferable as a storage device. Hard disks comes in sizes of 10M (the equivalent of 10,000,000 characters) to more than 1,000M (more than 1,000,000,000 characters) but most hard disks range between 20M and 80M. Virtual Disks X-DOS 5.0 lets you create one or more virtual (RAM) disks in memory. The reason for using a virtual disk is that the access time to a virtual disk is extremely fast; many times faster than a hard disk. You can install virtual disks in conventional memory, extended memory, and expanded memory with the virtual disk driver VDISK.SYS. ROM Disks If you are using X-DOS 5.0 from ROM, X-DOS will consider your ROM space as a disk too where one or more files have been stored for you. Refer to the X-DOS in ROM section to obtain more details. Wildcard Characters Two special characters called wildcards can be used in filespecs. These two characters are the question mark (?) and the asterisk (*). The wildcards are used in the specification of filenames to abbreviate the typing of filenames or to specify a range of files. As a unique feature, X-DOS also allows the use of wildcards with the CD command. The `?' wildcard is used in a filespec to replace any one character in the name or extension part. This way, any character can fill this place when X-DOS tries to match filenames. You can use multiple `?' wildcards in the filespec, each of which takes up the space of one character. Look at the following example: DEL LETTER?.T?? The following files will match this filespec and will be deleted from the default directory. LETTER1.TXT & LETTER4.TXT & LETTERS.TEX The following files will not match the LETTER?.T?? specification, since the `?' wildcard only replaces one character in the filespec, and they will therefore be left intact: LETTER10.TXT & LETTERS1.EXT 2-9 The `*' wildcard is used in filespecs to replace a range of characters. If you use the `*' wildcard in the name part of a filespec, it will replace the rest of the characters up to the extension part. If you have a filespec like LET*.DOC, X-DOS will try to match any files that have LET as the first three characters and .DOC as an extension. Look at the following example: COPY LETTER*.* X-DOS will copy all files with LETTER as the first six letters and any characters as the next two characters of the name part. The extension can be any valid extension. An often used wildcard combination is the *.* filespec specification. X-DOS will treat a specification like this as concerning all files in a specified directory. This allows you to easily copy, modify, or delete all files in a directory. Using Parameters (Options and Switches) Many of the X-DOS commands use parameters (switches) which modify the operation of the commands. Some even accept a range of parameters to tailor the function. X-DOS command parameters are always preceded with a delimiter, often a slash (/) or a space. Command Line Editing You should fully understand the functions and the power that you always have readily available from your keyboard to utilize X-DOS to its optimum. One of the very powerful features of X-DOS is its ability to let you save time by allowing you to recall previously executed commands and edit the current command displayed at the command line. Whenever you type a command or recall a previously executed command, you can always edit any part of it without having to delete portions of it. As a default X-DOS sets aside 256 bytes of memory to hold previously executed commands. This memory is called a history buffer. If you wish to increase the amount of memory allocated to the history buffer, you can insert the HISTORY statement in your CONFIG.SYS file and specify a value up to 2,048 bytes which 2-10 should hold more than 100 previously executed commands. You will probably find that the default 256 bytes of memory is enough. Command Line Editing keys The following keys can be used to edit commands at the command line: [Up] arrow key Recalls the previously executed command. [F3] function key Recalls the previously executed command the same way as the [Up] arrow key. This function key is set up to repeat the previously executed command for compatibility with the DOS standard. [Down] arrow key Recalls the last command in the history buffer. [Left] arrow key Moves the cursor one character to the left in the command which is currently displayed at the command line. [Right] arrow key Moves the cursor one character to the right in the command which is currently displayed at the command line. [Home] Moves the cursor to the beginning of the command currently displayed at the command line. [End] Moves the cursor to the end of the command currently displayed at the command line. [Ins] Toggles between insert and overwrite mode when editing commands. [Del] Deletes the character at the current cursor position. [Backspace] Deletes the character to the left of the cursor. [Esc] Clears the command line. [Enter] Executes the command currently displayed at the command line. You can execute a command even if the cursor is in the middle of the command. Function Keys X-DOS allows you great flexibility in the use of function keys by letting you set up to 39 function key assignments. You will not be able to redefine the [F3] function key since it is always set up so it repeats the previously executed command. This option can only be used if you set the FKEYS=ON switch in the CONFIG.SYS. By default and to respect compatibility with the DOS standard, this 2-11 switch was set to OFF. By assigning X-DOS commands or any other program names to function keys, you only need to press one key to execute X-DOS commands or programs. The Default Function Key Assignments If you choose not to define the function keys, X-DOS automatically assigns the following ten commands to the ten function keys [F1] to [F10]. <F1> HELP <F2> ED <F3> Cannot be redefined <F4> DIR <F5> MAPMEM <F6> ED <F7> DISKCOPY A: A: <F8> TREE <F9> CHKDSK <F10> XSHELL The ten function key assignments can be as long as 20 characters each. If you want to make permanent changes to the function key definitions, you can use enter the ALIAS command in your AUTOEXEC.BAT file. You can also change function key definitions permanently if you load the ANSI.SYS screen driver. Please refer to the ANSI.SYS command description later in this manual. X-DOS features five other hot keys that can be used to terminate the execution of programs, reboot the computer, or print the screen: [Ctrl]C or [Ctrl][Break] Stops the execution of a batch file or program. [Ctrl][Alt][Del] Reboots the computer and loads the system files again. [Ctrl]S Temporarily halts scrolling of the screen. Pressing any key will continue the scrolling. [Pause] Many of the newer keyboards feature a [Pause] key which works like the [Ctrl]S hot key sequence. [Shift][PrtSc] prints the contents of the screen to the default printer. Quick Keys A quick key is a highlighted letter within a menu. Quick keys are only used in those X-DOS commands that feature a full-screen display with men