JJ└└JO└¥£└OO└INSTALLATION OF A MINISCRIBE 70MB HARD TO MAKE A TWO HARD DISK SYSTEM USING"DISK MANAGER"¥£ TO OVERCOME THE 32MB LIMIT ON AN AT&T 6300.
by David Calabrese SLC Ut
I had run out of room on my 10MB hard disk on my 6300 and decided a second harddisk would give me more room and allow me to use the old 10MB as a backup disk.
There have also been several articles on using hard disks larger than 32MB Iended up buying the PC Magazine "editor's choice" a Miniscribe 72MB fromLifetime Systems. It came with the "editor's choice" Disk Manager software toformat and partition the large disk. I told them I needed a cable to hook bothto my western digital board and they threw one in. It was for an IBM only.
In order to eliminate problems with such an expensive purchase I had firstcalled the AT&T Technical Hot Line. They told me it would work and sold mesome cables. I called both Disk Manager and Miniscribe to ask aboutcompatibility and to help with settings. Sounds smart? Wrong! I ended upwith the wrong cables and wrong set up information. It took me four longevenings to figure that out. I probably hooked up all combinations of cables,dip switch settings and jumpers. I don't recommend this, but don't be tooworried about accidentally hurting something. I ran the Disk Manager Programabout 100 times using all options and generating most of its error messages. It is very good because one can always back out of it, it won't hurt itself orthe machine, and is easy to use.
Let's look at some ways to hook up and divide up the hard disks into differentdrive letters say "C" through "F" that will work with MS⌐DOS 3.2 FDISK command:
(DISK⌐1 The 10MB) disk physically hooked up as disk 1 and C: and (DISK⌐2 the 72MB) as D: and E: and F: divided in 3⌐24MB DOS⌐DATA partitions.
or make (DISK⌐1 the 72MB) disk physically hooked up as disk 1 with a .8 to 32MB DOS partition and several 1 to 32MB DOS⌐DATA partitions. with (DISK⌐2 the 10MB) set up as next drive letter as a 10MB DOS⌐DATA partition (drive letters are automatically assigned when system is first booted)
If one needs larger volumes or security then the Disk Manager is the way to go. Keep in mind that the MS⌐DOS FDISK command will not recognize or work with Disk Manager partitions, but it is not necessary because Disk Manager has its own FDISK equivalent. The DOS FDisk is not needed.
It also makes the following additional options available:
A read only partition that cannot be changed.
Partitions as large as the disk (with exception of the MS⌐DOS partition).
(DISK⌐1 the 10MB) disk physically hooked up as disk 1 and C: and (DISK⌐2 the 72MB) as D: with 1⌐72MB partition.
or make (DISK⌐1) the 72MB) disk physically hooked up as disk 1 with a .8 to 32MB DOS partition and one or more partitions in any size desired. (DISK⌐2 the 10MB) could be set up as 1 read⌐only partition after data has been stored on it.
▄j ▄î Before the actual installation begins it is helpful to consider how thecomputer works. When it is first turned on the BIOS scurries around and checksfor DOS in "A" drive. If it is not there then it tries to find a disk with acontrol jumper wire in the first or "terminator" position. That tells it tolook there and only there for the DOS command files. The next thing it does itlook on that disk for a partition marked MS⌐DOS. That tells it to look in thatpartition, (it is automatically always assigned the drive letter C:, regardlessas to where it is physically located, for the Command.com and other commandfiles. Everything else should be straightforward.
Some terms to be aware of:
C: DRIVE or VOLUME= MS⌐DOS PARTITION: (#1 Partition on an NEC). The only MS¬DOS partition allowed in the system . It contains command files whatever elseyou want to put in there.
DOS⌐DATA Partition: any other partition (Drive letter). One can run programsand store data the same as if it were a formatted floppy in "A" drive. DiskManager calls it a READ/WRITE Partition. It can be larger than 32 MB.
CONTROL CABLE A 34 pin ribbon cable that goes from the hard disk control card to one or two disks. The disks can be cabled in tandem or in a"Y" with each end terminating at a disk and a connector in the middle to attachto the controller. Connectors at ends must be correctly wired for disks thatthey attach to. The end that goes to the Miniscribe has wires #24 thru #29flipped⌐ (k#24 wire attaches to to #29 pin on the connector etc).
DATA CABLE a 20 pin ribbon cable going from the hard disk control card to ahard disk. One is required for each disk.
JUMPER or JUMPER BLOCK a tiny black block that bridges two resister wires. Usually located under or next to the 34 pin connector on the hard disk.
TERMINATOR The same jumper or jumper block when it is located on the first setof pins. Identifies that disk as C: (where Command.Com is located), to BIOS. Can be in that position on only 1 (you choose) disk. The other disk must haveits jumper block on the second or maybe third or fourth wires.
DAISY CHAIN: one after the other. Not a "Y" type connection
LOW FORMAT or INITIALIZE: usually done at factory. Disk Manager also does it. AT&T has a program called Low Form.(The instructions are not included to easilywork with two hard disks. AT&T information has not kept up with AT&T hardware.)
FORMAT or VERIFY or HIGH LEVEL FORMAT: a procedure carried out by the userafter partitioning and before installing files.
STANDARD DISK DRIVE: A disk drive supported by the rom BIOS of your computer. Check owner's manual. This is Disk Manager terminology.
RE⌐STRAPPING: remove controller card and check DIP switch settings againstlistings in owner's manual. Reset as necessary. Also check that the #1⌐20 pincable is plugged into #1 slot on controller card (directly under 34 pin socket)and goes to the disk that is chosen to be #1).▄j ▄î├ ((├â
├ (├¥SETUP & INSTALLATION OF TWO HARD DISKSâ
£This procedure will be useful for:
1. A single hard disk less than or more than 32MB.
2. A second internal hard disk.
3. A second hard disk externally attached to an AT&T 6300. Also useful for other machines with a small CPU that require an external disk.
SETUP:
1. Check owner's manual to make sure the disk to be bought is supported by ROM. For the 6300 use ROM 1.43 and pages 1⌐14 to 1⌐18 ¥£ 2. Inspect controller card to locate dip switches and check for two⌐20 pin cable sockets and one⌐34 pin cable socket. (If you are setting up two disks). If one hard disk is already installed the 20 pin cable should be in the #1 socket.
3. Set DIP switches according to manual and disks. Make sure that jumper block is on #1 position on disk that will hold DOS system files.
4. Check to see that the cables will be long enough to go to the back of the new disk(s) and if external to allow for a safe location of the disk.
a. The 6300 needs 12" of cable for the 20 pin cable to reach just outside of the CPU.
b. The 34 pin cable needs 12" from the controller card socket to the internal disk and 12" from the controller card socket to reach outside the CPU. The controller card socket is the center of a "Y" configuration.
c. The external disk can be in a box with its own power supply or use a 4 wire power cable in a "Y" shape with the arm to the internal disk as short as possible and the arm for the external disk 24" +distance to disk. I used AT&T power supply.
d. These dimensions will get the cables out of the CPU. Add whatever length you need to the cables so that they will reach the chosen external hard disk location.
e. There is a small knockout section on the left front side of the 6300 to allow the cables to exit. File sharp plastic point remaining.
f. IBM AT's or machines using 2 internal hard disks use standard length cables usually available from the hard disk vendor if asked for.
5. The jumper block on the 2nd hard disk (not the "C" drive) can not be on the #1 (terminator) position. It is usually on #2 position.
Well that's the hookup. Use the DOS FDISK command according to the owner`smanual or run a program like DISK MANAGER. Be aware that the partitions thatDISK MANAGER makes can not be operated on by the DOS FDISK command.
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My machine is set up as follows:
1. 1⌐external 70MB disk divided into two partitions with C: drive on it andone remaining large volume of about 70MB named D: drive.
2. 1⌐internal 10MB disk identified as E: drive and is used as a backup
Notes:
Two hard disk motors hum quite a bit and lead to operator fatigue after severalhours. I recommend you also purchase AT&T keyboard and monitor extender cablesand get the CPU under the desk. Put the second hard disk as far away aspossible or sound⌐insulate them.
I used a standard Bud Box CU 2110⌐B and made cutouts and bolted the disk to it. It's not fancy but it's back under the desk behind the CPU.
