lenny@icus.islp.ny.us (Lenny Tropiano) (09/02/89)
In article <938@cbnewsk.ATT.COM> ntj@cbnewsk.ATT.COM (najmi.jarwala) writes: |> ... |>I have a 20MB disk (Miniscribe?) and I have just obtained a 80MB Seagate |>ST4096 that I plan to install. The distributor assures me that it is a simple |>plug-out plug-in operation. Is it really that simple? Are there any pitfalls |>I should be aware of? |> Firstly, the Seagate ST-4096 is a 9 head drive, the UNIX pc (aka PC7300) can only handle 8 heads 1024 cylinders without ANY hardware modifications. So your 80MB drive is now a 67MB drive, oh well. Also you should be aware that the power consumption on the bigger full-height drives is much more than what your small half-height 20MB drive is taking... The PC7300 power supply probably can't handle that drive, so I'd suggest an external power supply cabinet for the ST4096, it's probably what you planned on doing since the PC7300 doesn't have the extra "hump" for the full height drives, unless you bought another top ... If you want the 20MB and 80MB drive both together you'll definately have to do the 2nd drive hardware modifications... E-mail me for further information... -Lenny -- Lenny Tropiano ICUS Software Systems [w] +1 (516) 589-7930 lenny@icus.islp.ny.us Telex; 154232428 ICUS [h] +1 (516) 968-8576 {ames,pacbell,decuac,hombre,talcott,sbcs}!icus!lenny attmail!icus!lenny ICUS Software Systems -- PO Box 1; Islip Terrace, NY 11752
res@cbnews.ATT.COM (Robert E. Stampfli) (09/04/89)
In article <953@icus.islp.ny.us> lenny@icus.islp.ny.us (Lenny Tropiano) writes: >In article <938@cbnewsk.ATT.COM> ntj@cbnewsk.ATT.COM (najmi.jarwala) writes: >|> >... >|>I have a 20MB disk (Miniscribe?) and I have just obtained a 80MB Seagate >|>ST4096 that I plan to install. The distributor assures me that it is a simple >|>plug-out plug-in operation. Is it really that simple? Are there any pitfalls >|>I should be aware of? >|> >... Also you should be aware >that the power consumption on the bigger full-height drives is much more >than what your small half-height 20MB drive is taking... The PC7300 power >supply probably can't handle that drive, so I'd suggest an external power >supply cabinet for the ST4096, it's probably what you planned on doing since >the PC7300 doesn't have the extra "hump" for the full height drives, >unless you bought another top ... Several comments: (1) Be advised that some of the 4096 drives that I have seen come configured out of the box to run in the MS-DOS world as a 2nd drive. You must change the addressing strap if such is the case before installing the drive on the 7300 or it will not work. (2) As Lenny says, you will need a pop-top or external case. I think the pop-top cases are still available from DDS, or whatever their new name is, in Georgia, at 2 for $50. They won't sell you just one, so you may want to try to find someone to go in on it with you. You will have to transfer the fan and connectors to the new case, but it is trivial. The new case comes with a new monitor. Don't try to reuse the old monotor on the new case unless you absolutely have to. It is a bear to change out only the monitor. My case had a hole for only one fan, but one fan seems sufficient to do the job quite well (but without any redundancy in case of failure). (3) The drive installs fairly easily, but the power connector is in a bad location for the 7300. It will (just) clear the rear flange on the case, so be careful when reinstalling the case after replacing the drive, so as not to damage the connector. (4) beware that the drive, as Lenny says, draws more power than the typical 20 Megger. I think the only potential (no pun intended) problem is the +12V supply, which on the 7300 is rated at 3.5 amps. The drive actually draws more than that on startup and something like 2.8 amps running (I am guessing here). However, I have known several people who are successfully running a 4096 off the vanilla 7300 (not 3b1) power supply, though, and none has had any problems that can be attributed to this yet. (Can anyone actually confirm a case where doing this caused problems?) One thing I would recommand is to get a power connector and run the drive directly from the power supply. There are solder holes for connecting a spare power cable, and it is a straight forward task to remove the supply and solder the cable in once the case is removed. Connect this to the 4096 and fold the other power connector into a corner. I *have* heard of problems trying to draw this amount of current thru the motherboard, and this seemed to be borne out on one system where we measured the voltage at the drive both before and after installing this direct power connector. (5) You may want to try to shield the drive from the monitor. I have never done this and have had no problems, but several people point to this as the cause of lost data. The jury is still out on this one. Hope this helps with your upgrade. You'll really love the larger, and presumably faster drive. Rob Stampfli att!cbnews!res (work) osu-cis.cis.ohio-state.edu!n8emr!kd8wk!res (home)