Path: utzoo!mnetor!tmsoft!torsqnt!news-server.csri.toronto.edu!cs.utexas.edu!uunet!shelby!snorkelwacker.mit.edu!primerd!hammer!cummings From: cummings@hammer.Prime.COM (Kevin Cummings) Newsgroups: comp.sys.ibm.pc.hardware Subject: Re: 2 hard drives in 1 machine...HOW? Message-ID: <1991Feb13.180633@hammer.Prime.COM> Date: 13 Feb 91 23:06:33 GMT References: <1122@applix.com> Reply-To: cummings@hammer.Prime.COM (Kevin Cummings) Organization: Prime Computer R&D Lines: 137 Nntp-Posting-Host: hammer In article <1122@applix.com>, jimr@applix.com (Jim Rouleau [ext 256]) writes: |> |> OK, here we go... I am trying to install 2 hard drives in my AT. I Well, I have installed a second hard drive in my PC. So it can be done. |> haven't seen much info on the subject and I've asked around to no avail. |> (The drives are a Micropolis 1325 and a Miniscribe 3425). I've lots of |> questions, bear with me. OK, these are both ST506/ST412 interface drives. (MFM to some.) |> The controller cable I'm using has the card connector, some straight |> cable, connector '1', a twisted section, and finally connector '2'. |> |> X----------X---------X |> X----------X--\-/----X not perfect, but you get the idea. |> X----------X---|-----X |> X----------X--/-\----X |> '1' '2' Hmm, I replaced the twisted cable with a straight through cable. I then strapped each drive so that it worked. Remember to hook up the data cables too. B^) And since you can boot either drive independently, I'll assume you're getting the cables plugged in right. Are your edge card connectors keyed? Especially '2'? |> Anyway, each drive will boot the machine if I connect it to |> connector '1'. What I would really like is to boot the machine with |> the Micropolis and have the Miniscribe be drive 2. (but I'll take |> the other way If I could even get that!). I've tried different combos |> with no luck. I have configured the CMOS, so that's no problem. |> I've also tried just booting the machine with either drive attached |> to connector '2' and changing the select jumpers, but haven't been |> able to boot the machine by doing this. I assume that I have the |> jumpers set to drive select 1 when I am able to boot them |> separately. In theory, you should be able to correctly set the device jumper on your hard drive, and plug the data cable to the right data connector on the controller, and it should work. |> What makes a drive first or second and how does the machine |> distinguish them? Is is just the data cable or does the controller |> cable play too? (Does anyone know 'why the twist'? I,ve heard |> "hard drive cables are different than floppy cables", but isn't |> the twist the only difference?) What about the terminating resistors? |> Do I want the first physical drive on connector '1' or '2'? Good question. I'm not sure of the specifics, so if I screwed up the real drive device selections, please don't yell at me. After all, I got *MY* system working! Besides, I am at work right now, and can't look at the actual configuration I have at home. The PC considers Device 1 (not 0, 2, or 3) as the first drive. The second device is also configured as device 1, but is accessed after the flip in the cable and is actually responding to another device line from the disk controller. (Could be either Device 0 or Device 2, I forget, but supposedly the cable flip also flips the other two device numbers as well. Say: "Thank you IBM".) The fact that your disks will boot the machine when plugged into connector '1' while configured as device 1 rules out the possibility of the machine trying to boot from device 0. Now all you have to figure out is if the second drive is device 0 or device 2. With the flip in the cable, you should jumper it as device 1. Without the flip in the cable, you must jumper the drive correctly. Don't forget that a SEPERATE data cable must go from the controller to the second hard drive. The control cable is dasiy chained, but not the data cable! (But then you knew that, right?) |> Another thing, what about the partitions? Right now I've got a |> bootable partition on each drive. Will DOS be nice and allow me |> to change the logical drive of the second physical drive so that |> if the last logical drive of the Micropolis if E> and I cd to |> F> then I will be accessing the Miniscribe? Or do I have to change |> something first, while I can still access each drive as the first? Here is where I think you are getting into trouble. I had some problems partitioning my second hard drive. What works is: Create only an EXTENDED DOS PARTITION on the second drive. Don't create a PRIMARY (bootable) DOS PARTITION. I found out the hard way that you can't access any bootable partitions except the one you booted from! Actually, because my second drive has > 1024 cylinders, I used SpeedStore to FORMAT/PARTITION my entire second drive so I could access all 80MB (instead of the 60MB using only 1024). But I did determine that my drive worked by formatting it via my BIOS, and then partitioning it with FDISK first. Your C: disk is always the bootable partition on the first drive. I believe that how the rest of the drives get allocated if a function of whether or not you're using device drivers, or DOS drivers, and the version of DOS you are using. Under DOS 3.2, drive 1 is always C:, and drive 2 is always D:. DOS 3.2 doesn't support drive partitioning, you must use a partition manager (Disk Manager, SpeedStore, etc). These extra partitions get allocated IN THE ORDER THEY APPEAR IN YOUR CONFIG.SYS FILE. I can't emphasize that enough! If you have a RAMDISK driver before your disk partitioning driver, then your RAMDISK becomes E:, and your partitions start with F:. Under DOS 3.3, DOS loads enough device drivers during cold start to support your partitioned drives sequentially. So your first drive is always C:, any extra partitions on the first drive come next, followed by the second drive, and any extra partitions on it as well. Lastly come any extra device drivers you load in CONFIG.SYS (like a RAMDISK). Yes, adding a new disk might shift around the logical drive names you were used to. Then again, depending on the version of DOS you are running, it might not. Right now, on my system, C: is the DOS PRIMARY, D: is the EXTENDED on the same drive. E: is a SpeedStore partition on the first drive (cylinders 1023 -> 1165). F:, G:, and H: are also SpeedStore partitions on my second drive (all 26MB partitions, it was easy to do it that way.) |> As you can see, I have got a lot of bits and pieces, but haven't |> managed to piece them together coherently enough to form the picture. |> I might be the only one who doesn't understand this, but if there's |> enough interest I'll post a summary. Good luck with your configuration. I hope all of this is clear. If not, let me know, or post another followup, and we'll try again. Your installation should be easier than mine because your disks both have <= 1024 cylinders, and shouldn't need extra device drivers like mine did. ================================================================= Kevin J. Cummings Prime Computer Inc. 20 Briarwood Road 500 Old Connecticut Path Framingham, Mass. Framingham, Mass. InterNet: cummings@primerd.Prime.COM UUCP: {uunet, csnet-relay}!primerd.Prime.COM!cummings Std. Disclaimer: "Mr. McKittrick, after careful consideration, I've come to the conclusion that your new defense system SUCKS..." -- War Games =================================================================