 The magazine of the Melbourne PC User Group A Beginner's Tale: Part 18 Ron Wilby |
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Welcome to all you readers out there. What would I do without you? Get some sleep? What do you think of Charles leaving us in pursuit of beastly money? And what about all this talk of faster chips which will easily outdo the Pentium. Do we really need all that processor speed? I think not, see Tom Coleman in PC Update April 1994. This month Ron gets caught (again) sleeping at the keyboard in dead of night and has to do some quick study of the DOS UNDELETE facilities.
Undeleting
Recently, working away in the small hours, I was stupid and made the inevitable mistake. I wanted to clear an old floppy with which to send off the next episode of The Beginner's Tale. Of course I forgot to change the default drive to B: and typed DEL *.* at the prompt. Unfortunately the prompt was C:\, so DOS deleted files in the root directory.
Don't panic, Ron!
Don't touch the keyboard!
Don't switch off, you have just lost your Startup files. If you reboot, there will be no AUTOEXEC.BAT and CONFIG.SYS files to activate UNDELETE.
RTFM (read the flaming Manual)!
Recovery
What to do? Simplest method, type UNDELETE and get back all those files. I did that and wasn't surprised when nothing happened. Next, call up that clanky DOS 6.2 MS-Help system. It seemed I must look at my AUTOEXEC.BAT file to see what, if any, undelete methods are in use. Great, thanks Microsoft, I just deleted AUTOEXEC.BAT. It was beginning to look like a tedious session with a backup tape, which would, of course, have solved the problem.
By this time my curiosity was awakened. Does UNDELETE really work? Following the Manual, you type UNDELETE at the prompt. What you get is a message saying that 38 files can be recovered, but nothing is happening to recover them. What now? I tried various things, like typing UNDELETE *.*, but no result.
My unreliable memory told me that one of the boot-up screens mentioned Delete Tracking. Perhaps that's it, but don't reboot, you probably don't have either AUTOEXEC.BAT or CONFIG.SYS. files any more. With a stroke of the inspired genius always needed when dealing with DOS 6, I tried the command UNDELETE /DT and behold, got all my files back one by one, completely unharmed. Why /DT? Stands
for Delete Tracking of course, but this information is only found on p.580 of the DOS 5 Manual. That useless DOS 6.2 Manual, as usual, tells you nothing much and suggests use of Help screens. The /DT switch is mentioned there, but it isn't really when and why you should use it.
Delete Sentry
There are three levels of Delete protection available in DOS 6. The highest level, Delete Sentry, keeps a copy of deleted files in a hidden file. However, the size of the Sentry file can be enormous. The DOS 5 Manual mentions a maximum size for the Sentry file of 7 percent of your hard disk. That's around 17 MB in my case, a bit too much, you think? Try DOS 6.2 then. There is a file called UNDELETE.INI which allows the maximum size of Sentry to be 20 percent of your disk, or 50 megabytes in my case. You can change these figures, but it's all a hassle. I'll stick with the Delete Tracker, I don't delete all that many files by mistake. Also, to get rid of old files from the Sentry file involves a tedious purging routine.
Delete Tracker
The next level down is Delete Tracking, which uses MIRROR to keep track of deleted files. The location of deleted files is placed in a file called PCTRACKR.DEL. This works fine, as I have just demonstrated, and uses less disk space. Of course, the weakness of Delete Tracking is that the stored locations may be overwritten if you don't act promptly. Your files will then be impossible to recover. The third level is the standard method, where DOS brings back the files with the first letter of their names replaced by #. You are then asked for the missing first letter. If you don't know or don't remember, type any letter, and DOS will proudly announce that your file has been successfully recovered. What rubbish. What, for example, is #C.EXE? If, like me, you had deleted many files, you wouldn't remember all the names, so like me, you would have to go to your backup disks or tapes.
DOS Version 6.x
Unhappy with the never-ending problems of successive versions of Microsoft's MS-DOS? Would you like to produce your own DOS? You can, at a price. Selecting utilities from the DOS alternatives, IBM's PC-DOS 6.1 or Novell's DOS 7 may help. Let's consider some of the possibilities.
Disk Compression
With DOS Version 6, a new and potentially valuable disk compression utility called DoubleSpace appeared. However, DoubleSpace brought with it a host of problems specific to DOS 6.0 and
6.2. Microsoft, faced with a choice of compression systems, evidently made a bad decision. There were troubles with data corruption with DOS 6.0, so ScanDisk was introduced to cure that. Then ScanDisk was found to be causing the total loss of data on certain hard disks and that had to be cured too. The sad part of this is that even when working perfectly DoubleSpace is not very good. The alternatives you could consider for your own DOS 6.x are the popular Stacker, which comes with Novell Dos 7, and Superstor, which comes with IBM's DOS 6.1. A test recently published revealed that Stacker and Superstor each provided some 20 MB more free disk space than did DoubleSpace. Additionally, Stacker and Superstor can create compressed floppies which can be read by any PC (DOS 6.2 can't do that) and PC-DOS 6.1 (Superstor) can read Stacker-compressed drives directly (6.2 can't do that either).
Data Protection
PC-DOS 6.1 offers a full-screen Undelete feature as does DOS 7, with 6.1 being much easier to use. MS-DOS has a command UNDELETE (see above) with inadequate documentation which makes life difficult. Backup facilities present different pictures. Hard disk sizes are rising, even newcomers to the PC world are buying 100 MB disks as standard. 250 MB and more are common. Do Microsoft and Novell really expect us to back up these disks to floppies? Apparently they do, since their backup utilities don't support tape drives at all. MS-DOS doesn't even support high-speed backups to floppies, you need to go to PC Tools or Norton for that. PC-Dos 6.1 is a clear winner here, using backup programs licensed from Central Point (PC Tools) which work with floppies or tape drives. As I found out recently with my latest computer upgrade, the software that comes with tape drives is generally pretty awful and PC-DOS 6.1 is a great improvement. An alternative to MS-DOS is therefore to go out and buy IBM's PC-DOS 6.1, but of course there is a cost penalty. MS-DOS 6.2 has been available for around $100, while PC-DOS may cost up to $190.
That's all for now. Till next month
Reprinted from the June 1994 issue of PC Update, the magazine of Melbourne PC User Group, Australia
