Path: utzoo!mnetor!tmsoft!torsqnt!lethe!yunexus!ists!helios.physics.utoronto.ca!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!applix!jimr From: jimr@applix.com (Jim Rouleau [ext 256]) Newsgroups: comp.sys.ibm.pc.hardware Subject: Re: 2 hard drives in 1 machine...HOW? Message-ID: <1129@applix.com> Date: 19 Feb 91 17:49:45 GMT Organization: APPLiX Inc., Westboro, MA Lines: 153 I got about a dozen responses, thanks to all of you who took the time to do so. I resolved my problem, which turned out that I was indeed using a set of floppy cables. When I changed them everything fell together very nicely. From the responses I will attempt a summary. Anything after a >> is stuff that was submitted but, although I'm not sure about it, I'll include it anyway. Disclaimer: I haven't verified all of this information, and of course there may be differences among machines, controllers and drives. Feel free to use any of this information in any way you please, but if somthing goes wrong don't blame me. Let's start with that cable. Both the floppy cable and the hard drive (controller) cable are 34 wire ribbons. For hard drives, 5 wires (6 thru 10) are twisted and for floppies, 7 wires (10 thru 16) are twisted. What these twists do is muck with the drive select lines. As far I as I know, the following applies only to hard drives. (but that's only because I haven't has to deal with floppy drives ... yet). >> At Controller Connector 1 Connector 2 >> -------------- ----------- ----------- >> Select line 1 Select line 1 Select line 4 >> Select line 2 Select line 2 Select line 3 >> Select line 3 Select line 3 Select line 2 >> Select line 4 Select line 4 Select line 1 Note: Many hard drives (meaning MFM and RLL) have four drive select settings although most drive controllers support only two hard drives. The bios supports two hard drives. Make sure the settings are correct for both drives. It seems that what the controller expects to find is drive 1, then drive 2 but, perhaps historically ... maybe the drive selects on some drives couldnt be changed ... the twist allowed a way to change the drive select without physically changing a switch on the drive. So if the drive is configured as drive 2 but put after a twist then it will be seen as drive 1 and if it is configured as drive 1 then after a twist it will act as drive 2. When I realised what was happening here, it all made good sense ... sort of like (-1)(-1) = 1. Some submitters said the first drive must go in the middle, some said it must go on the end. What I found is: it doesn't matter! What is important is not which if first physically, but 'logically' You don't even need a twisted cable. Use one of the following: connector select drive 1 1 1 twisted cable drive 2 2 1 connector select drive 1 2 2 twisted cable drive 2 1 2 connector select drive 1 1 1 straight cable drive 2 2 2 connector select drive 1 2 1 straight cable drive 2 1 2 There is also the 20 pin data cable, but you need 1 for each drive and they are identical. Just be sure that connector 1 on the card goes to the first drive and connector 2 goes to the second drive. Also ensure that wire 1 on the cable (with a colored stripe) gets connected to pin 1 on the connectors. Most of the drives are 'keyed' with a slot on the connector and a plastic tab in the plug to prevent you from inserting them the wrong way. These keys are removable (unless they,ve been glued!) if you need to change the connector around. The card and the drive are also usually marked as to which is pin 1. Finally there is the termination resistor. There should be 1 and only 1 termination resistor in the system and that should be on the drive that is at the end of the controller cable. If you leave the resistors on all the drives everything will still work, but you may be risking some future overheating problems. That should take care of the hardware. The partitioning issues were not nearly as clear. There are a lot of programs around to handle these things (Ontrack disk manager, SpeedStor) and they have ways of doing things like marking a partition as theirs to get around the 32Meg limitation before DOS 4.X. What seemed to be the cleanest and most agreed on was that there should be no bootable partition on the second drive. If there is, that should be changed to 'usable' but not bootable before the hookup is made. Responses ranged from ' Otherwise you will get CEF on 1st one and DGH on the 2nd one.' to 'I found out the hard way that you can't access any bootable partitions except the one you booted from!' My personal experience was that 'C' became partition 1 drive 1, 'D' is partition 1 drive 2, 'E' and 'F' are partitions 2 & 3 respectively on drive 1. I may be able this change this with Ontrack or the like, but I think I'd prefer to leave things alone. After everything was up and running, FDISK allowed me to select each drive and partition as I liked, with the 32Meg restriction since I use DOS 3.3. Miscellaneous notes: (as submitted) If you want more than two hard drives, you need a special drive controller and special software. One good example is any SCSI host adapter. If you want to boot from 2 or more partitions (you have 2 or more OS), try 'BOOTMENU' software. This freeware can manage 3 bootable partitions on your C: drive, and you can select which partition you boot at power on or reset time. I have 3 bootable partitions on my c: drive, DOS 3.31, DOS 4.0, and OS/2 1.2 (and one data partition). One draw back is; if you boot from one partition, you can't access other boot partition. If you want to boot off of either drive directly I've heard of - but have not used - a program alled "bootany.*" that's available from the simtel archives. I've even gotten gutsy and tried a MFM with an RLL. (worked but supposedly not very reliable). Personally, I'd make a 2-3 Mb partition at the beginning of the boot drive to store the DOS or OS/2 (whatever). This way, it makes it easier for you to upgrade to the next version w/o redoing the whole drive. If your config.sys has a last drive command (like there is with dos 4.0), you may have to change the last drive to a letter beyond what you would get when you add the second hard drive. I would recommend that you back up and everything first! Finally, I must pass on the following request: >From uunet!WISCSSC.BITNET!LENG Fri Feb 15 05:22:56 1991 >Return-Path: >Received: from applix.com by jimr.applix.com (4.1/SMI-4.1) > id AA20539; Fri, 15 Feb 91 05:22:50 EST >Received: from uunet.UUCP by applix.com (4.1/SMI-4.1JJM) > id AA02138; Fri, 15 Feb 91 05:25:51 EST >Received: from cunyvm.cuny.edu by uunet.uu.net (5.61/1.14) with SMTP > id AA15512; Thu, 14 Feb 91 22:04:52 -0500 >Message-Id: <9102150304.AA15512@uunet.uu.net> >Received: from WISCSSC.BITNET by CUNYVM.CUNY.EDU > (IBM VM SMTP R1.2.2MX) with BSM >TP id 8367; Thu, 14 Feb 91 22:05:20 EST >Date: Thu, 14 Feb 91 21:02 CDT >From: >By the way, can you kind enough to post a help message on the USENET for me? >I want to know the jumper setting for Micropolis 1325 MFM 71mb hard drive. >Now I can read the USENET but can't post. Thanks in advance. > Leng@sscb.ssc.wisc.edu which is ok by me, since the Micropolis drive I'm using is a 1325 !!