hsc@mtuxo.UUCP (h.cohen) (06/28/86)
I have deleted the author's name to avoid personal interruptions to the author. *** Process with tbl, nroff/troff and mm macros*** .TL Formatting Tracks as Bad for Bad Track Handling (UPDATE) .AU .MT "" Attached are detailed instructions on detecting and formatting tracks as bad on 20, 40 and 68M hard disks. These instructions should be followed only if you suspect that the bad tracks on the hard disk are not marked as such, or if you have run the diagnostics' low level format. They should not be used for correcting problems after the machine has been loaded. .SG et .NS All Members Department 60545413 M. Askinazi B. T. Burger K. Cochran H. Cohen J. E. Dawson J. G. DeFelice P. A. Farago M. W. Goldstein K. W. Gould M. D. Jackson K. M. Keverian J. I. Kiger E. Kuhn L. D. G. London M. McKinstry L. E. Menten C. M. Murphy G. K. Nandakumar C. K. Nemovicher P. Rabinowitz A. Sparling M. I. Steinberg S. A. Tartarone A. K. Todres J. B. Urban L. C. Zeglarski .NE .sp 15 .P The Bad Track Handling feature of the PC 6300 PLUS handles two different situations; tracks that are marked bad prior to UNIX installation and tracks that go bad through use after UNIX installation. If tracks are marked as bad prior to UNIX installation, then the UNIX system knows these tracks are not accessible and alternate tracks are allocated for them. If tracks go bad through use then the Bad Track Handling feature allocates alternate tracks for the bad tracks, and tries to recover the data on the bad tracks. .P On the label of your hard disk is a list of tracks that the factory believes are bad. If the hard disk is from an external supplier, there is a chance that these tracks may not have been physically marked as bad on the hard disk. Loss of data may occur if they weren't marked as bad because UNIX would have written to the track assuming it was good. .P So, to ensure that your hard disk has all tracks marked as bad, the following steps should be taken. \fBCAUTION:\fP These steps should only be followed prior to loading the system the first time on the disk. If any tracks go bad through use, they will be found automatically. .P Through the diagnostic floppy, the following steps will remove all the bad tracks from the hard disk, verify the surface to pick up any tracks that are considered bad, create a internal bad track table and then physically mark the tracks that were in the bad track table. .sp 3 .DS C STEPS FOR 20MB HARD DISK .DE .AL .LI Boot MS-DOS System diagnostic floppy. You receive this floppy with the AT&T Personal Computer 6300 PLUS Service Manual. .LI Execute \fIsystem\fP .LI Answer 0 on first menu to execute the tests once. .LI The diagnostics will print information about the system configuration and the hard disk characteristics. Press the return key after each set. .LI You will be asked if you have a mouse on the machine. Answer yes or no. .LI You will be asked if the list of hardware printed is correct. Answer yes or no. .LI Then the list of hardware will be printed. Select the number associated with your hard disk. (Ex. 9). .LI You will then be asked if you want to pause on any errors detected. Answer no. .LI You will then be asked the number of retries of each test. Answer 0. .LI Select HDU selection #12 (Low Level Format). Use the default interleaving (3). .LI When the low level format is done, you'll be asked if you want to edit the bad track table. Answer no. .LI The HDU Test Selection menu will be printed again. Select #5 (Verify Surface). This will find all the bad tracks on the hard disk. .LI When the verify surface is complete, you'll see the HDU menu again. Select #14 (Display Bad Track Table). .LI If there are tracks that are on the label on top of the hard disk but not in the bad track table, you will want to add them. These tracks are called marginal tracks. They may not be bad enough to show up all the time. To add them, go back to the main menu for HDU selection and select #15 (Format Bad Tracks). Answer \fByes\fP to editing the Bad Track Table. .LI You will see another menu. Enter selection #1 to add tracks to the Bad Track Table. Follow the prompts. .LI When you have added all the tracks, exit from adding tracks and select #0, the option to mark them as bad. .LI To exit diagnostics, select #0 to return to main menu, and follow path back to the Testing Options menu and select #4 to exit. .LI Once the tracks are marked as bad, you're finished. The hard disk is now setup for loading the UNIX system. .LE .sp 3 .DS C STEPS FOR 40MB and 68MB HARD DISKS .DE .P If you are using a 40 or 68MB hard disk as the first drive, the low level format option of diagnostics will not work. It does not cover the whole disk. In order to accomplish the same effect, do the following steps prior to running the diagnostic floppy. .BL .LI Boot off MS-DOS System Disk. .LI Once it is booted, remove system disk and put in supplemental disk. .LI Type \fBdebug\fP. The following table represents the input and the output of the command. .TS c c l l. ENTER COMMAND RESPONSE ON SCREEN SHOULD BE debug<CR> - i 321<CR> CO - o 322 0<CR> - i 321<CR> CD - o 320 04<CR> - o 320 00<CR> - o 320 00<CR> - o 320 00<CR> - o 320 03<CR> - o 320 07<CR> - .TE .P At this point the drive activity LED should come on, and the drive will begin to format. When the process is complete the activity LED will go out. The process should not take anymore than 15 minutes. .LI Follow steps 1 to 17 listed under the 20MB hard disk, skipping step 10. .LE .P If you are using a 40 or 68MB hard disk as the second drive, the previous steps apply except for a one line change in the \fBdebug\fP command lines. The command lines for a second drive are the following: .SK .TS c c l l. ENTER COMMAND RESPONSE ON SCREEN SHOULD BE debug<CR> - i 321<CR> CO - o 322 0<CR> - i 321<CR> CD - o 320 04<CR> - o 320 20<CR> - o 320 00<CR> - o 320 00<CR> - o 320 03<CR> - o 320 07<CR> -