The Business Master (3rd Edition)

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Using MS-DOS 3.1 on an IBM PC by Mark S Cathcart Systems Engineer Chemical Bank 200 Jericho Qaudrangle Jericho NY 11753 AUGUST 26,1985. In an effort to organize my IBM PC XT/370 and its hard disks as well as to ease the pains of chaNgi.g from version to version of MS-DOS I have spent some time digging into MS-DOS and some of its standard features. What follows are a number of well known MS-DOS tips as well as some undocumented features of some of the MS-DOS components and some uses that may not have been thought of. I am not trying to tell you how to organize your PC but rather suggest a few things you might consider. "TRUE REFINEMENT SEEKS SIMPLICITY" I will be discussing the following topics: CONFIG.SYS - SHELL,LASTDRIVE COMMAND.COM PATHing SUBST command CHDIR command The MS-DOS PROMPT ANSI.SYS BAT files Environment Area CONFIG.SYS ---------- Two important parameters are found in this file (in terms of this discussion !) they are SHELL= and LASTDRIVE= . I will discuss them in reverse order. LASTDRIVE= was added in MS-DOS 3.1 as part of the PC Network support. You can specify the drive letter representing the last drive you wish to access. The importance of this parameter in this discussion is that it gives us the ability to access upto 21 logical disk drives via the SUBST command. Format: LASTDRIVE=n: where n: is drive A:-Z: Remarks: There seems to be no restriction on the coding of this parameter, you can specify Z: even if you have only one diskette drive. VM/PC users should be aware however that you should not go beyond the letter O: otherwise you will experience un-predictable results. This has been reported to IBM and has been closed as SUGGESTION for FUTURE IMPROVEMENT. SHELL= This parameter tell MS-DOS where to find COMMAND.COM . It is generally believed that this file has to reside in the root directory of the disk that is booted from, not so. There have also been a number of documents/programs showing methods of enlarging the MS-DOS environment area. At best some of these are risky, at worst they are down-right dangerous. You can via the SHELL= parameter change the size of the environment area as needed. Format: SHELL=[n:][path]filename.ext [n:][path] /D /P /F /E:nn Remarks: The first dive-path-filename.ext tells the system where to find the initial copy of COMMAND.COM to load. The second drive-path tells the system where to find the COMMAND.COM to reload when required. /D parameter tells MS-DOS not to executes the AUTOEXEC.BAT file at BOOT up time. /P parameter tells MS-DOS to make the substitution permanent. /F parameter tells MS-DOS to skip the response to the interrupt 24H handler message ABORT,RETRY or IGNORE . /E parameter tells MS-DOS how many paragraphs to set aside for the environment area. This can be between 10 and 62. The Default is /E:10 With the addition of a carefully coded SHELL= statement in the CONFIG.SYS file we can now put all files for a given version of MS-DOS into a separate sub directory. This is with the exclusion of the IBM BIOS/DOS files, which are created by the SYS command or FORMAT with with /S parameter. Also now the drive that you are booting from does not have to contain the COMMAND.COM file. So much for CONFIG.SYS, depending on your level of PC knowledge by now you are either bored,confused or want to know more. Stick with me. "NO MAN IS USELESS, HE CAN ALWAYS SERVE AS A BAD EXAMPLE" A habit that almost all hard-disk drive users have is to keep their files in sub-directories according to file type/use . This can be very helpful when trying to locate a file (or program), keeping multiple copies of files and even to some extent protecting files from prying eyes. One difficult part of doing this is accessing these files easily and being able to execute the programs without typing extensive and lengthy path names. One way of executing the programs is to code the sub-directory names in the PATH statement. There is (obviously ??) a problem with this though, you can only have one PATH statement, that PATH statement can only be 127 characters in length. I soon exceeded that. Assume for 1 minute that you have some directories named as follows: C:\DOS31 C:\PROGRAMS C:\PROGRAMS\BAT-AIDS C:\PROGRAMS\PASCAL C:\PROGRAMS\PASCAL\SOURCE C:\PROGRAMS\PASCAL\TUTOR C:\PROGRAMS\NEWPROGS C:\PROGRAMS\OLDPROGS C:\PROGRAMS\PC-GAMES (yes, I do have a few.) C:\COMMS C:\COMMS\XTALK35 C:\COMMS\PC-TALK I have these and many others on the C: disk alone not to mention the D: disk or any others I may be using. A quick glance should tell you that you cannot possibly PATH to all these subdirectories, let alone any more. Or can you ? As described above you can use the SHELL= parameter to specify upto 26 drive letters that need not all exist. When used with the SUBST command this can be a powerful tool. Lets take a look at the SUBST command. SUBST n: [n:][path] n: is a drive that you dont really have hardware for. [n:][path] is a disk subdirectory that will be searched when you specify n: For example: In the above list of directories the C:\PROGRAMS directory is referenced a great deal, we could code that: SUBST P: C:\PROGRAMS If we then do a DIR P: all the files in that directory will be listed. Also the PATH command can now be coded as PATH=P:;P:\BAT-AIDS;P:\PASCAL............ etc. This avoids needless repetition and allows to a greater number of sub directories within the PATH command. With this method I PATH to 32 directories that all have meaningful names. And this leaves my root directory to be used for data files only. This only presents one problem, getting to the subdirectories when you want to access the files or do some kind of maintenance to them. This is acheived by the CHDIR command in MS-DOS. To get to the subdirectory that contains the source for my PASCAL programs I would enter CHDIR C:\PROGRAMS\PASCAL\SOURCE which can be a pain if done often. PC Magazine Volume 4 Number 16 carried an article in its user-to-user column describing BATMAKER.BAS a BASIC program that created bat files with the name of the last subdirectory in a given path. From the above example C:\PROGRAMS\PASCAL\SOURCE could be goto by typing SOURCE . My implementation OF BATMAKER can be found on the ISA-PC RBBS. Mine differs from the one in PC-Magazine in two ways; one it is executed from a BAT file that always issues "CHKDSK / V | FIND "Dir" > TEMPFILE" and two all the BAT files are kept in another subdirectory so that they can be erased before each run of BATMAKER. If you are an MS-DOS expert by the time you reach this point you will trying to decide if you should read any more or quit, to you I say "PATIENCE IS NOT PASSIVE, ON THE CONTRARY, IT IS CONCENTRATED STRENGTH" Another hassle when working with many subdirectories is knowing which one you are in. The following example of the PROMPT command will solve this for you and it will also show you how to set the SCREEN attributes in a way that they will be reset following exit from a program (not always the case in standard MS-DOS!!). PROMPT $e[1mReady$e[0m($e[7m$p$e[0m)$e[1m;$d / $t$h$h$h$e[0m$_ ----- ----- ----- ----- ----- ----- The $p will display the current directory the $d causes the date to be shown the $t causes the time to be shown Most of that should be old hat to you right ?? The rest of the information not under-lined is makes the PROMPT a little prettier(?). The data under-lined represents escape sequences used to set the color and highlighting each time the PROMPT is displayed. I only have a Mono-chrome monitor and thus have not tested but believe the following codes to be true: $e[0m = Normal $e[1m = Highlight $e[7m = Reverse video $e[4m = Underline $e[5m = Blink $e[8m = Dark(invisible) $e[30m= Black $e[31m= Red $e[32m= Green $e[33m= Yellow $e[34m= Blue $e[35m= Magenta $e[36m= Cyan $e[37m= White You will be able to do much more than this but its upto you to test which you find best, the escape sequences are valid upto 49 I think. Note that to make use of these escape sequences you must include DRIVER=[n:][path]ANSI.SYS in the CONFIG.SYS file. And now before you go let me quickly talk about BAT files. BAT FILES ---------- These are a few simple tips on writing BAT files, the format and operational characteristics of BAT commands changes from release to release. Hopefully IBM will realize that this can be an important part of MS-DOS and will stop mucking about with it, document it properly and who knows, even develop it. Cause a blank line to be output enter "ECHO. " note that there is a period following ECHO, this will not be printed. Test for positive condition using IF subcommand when a replaceable parameter %1 %2 %3 etc. may not have been supplied if $%1==$START goto START this statement will execute correctly regardless if %1 has a value or not. Setting and retrieving information via the MS-DOS environment area. The environment area is where your PATH, PROMPT and COMSPEC values are kept and retrieved by MS-DOS. You can make use of this area as well. To set issue SET name=value To retrieve if $%name%==$YES echo YES Note that when you SET the value you DON NOT put it % signs but when you want to test the value you must include the name in % signs. Unless you specifically reset the values they will last until you re-boot or power off the PC. You should also be aware that you can run out of space to set variables, this is especially true if you use any memory resident MS-DOS programs such as SIDEKICK, DOSEDIT etc. To create more space change or add the /E parameter to the SHELL= statement in your CONFIG.SYS as detailed above. And finally, if you read all the way thru I hope you found this to be of some use, remember: "There are few things more difficult than the art of making advice agreeable."