shimoda@rmi.UUCP (Markus Schmidt) (03/20/88)
Hi! I recently posted a message about a german magazin, giving a interface for an amiga-harddisk. The magazine is now out. It is an interface for the amiga to connect a OMTI-controller to the amiga (1000 & 2000 as far as I know.) Cost will be about $15 for hardware and $15 for the driver. If anyone is interested, we could manage to get the magazine to you or to get you the address of the publisher. (Still don't have it, sorry) C u Markus (shimoda@rmi.UUCP) I have no relation to the publisher of the article or with anyone related to it.
wdg@unccvax.UUCP (Doug Gullett) (03/22/88)
In article <926@rmi.UUCP>, shimoda@rmi.UUCP (Markus Schmidt) writes: > > Hi! > > I recently posted a message about a german magazin, giving a > interface for an amiga-harddisk. The magazine is now out. > It is an interface for the amiga to connect a OMTI-controller > to the amiga (1000 & 2000 as far as I know.) Cost will be about > $15 for hardware and $15 for the driver. I am not familiar with OMTI-controllers. Could someone fill me in about them. thanks, Doug Gullett University of NC at Charlotte
lai@vedge.UUCP (David Lai) (04/13/88)
In article <938@unccvax.UUCP>, wdg@unccvax.UUCP (Doug Gullett) writes: > I am not familiar with OMTI-controllers. Could someone fill me in > about them. I think what they are referring to are SCSI to ST506 adapters manufactured by OMTI. I'm not sure if OMTI is still in business or not but I have the following number: SMS (don't know what it stands for) phone (415) 964-5700 (I think they either manufacture the boards, or bought out whoever used to). If you look in the back of BYTE, there are various surplus houses selling OMTI controllers: March 1988, page 304, Computer Surplus Store (408) 434-1030 * March 1988, page 315, California Digital (213) 217-0500 * they will sell you a manual for $8 I think I saw a manual for the 20L once, and it is just another generic SCSI/ST-506 adapter. Why the OMTI controller was chosen for this low-cost project is probably because it is CHEAP (old technology, and probably out of manufacture/unsupported).... therefore perfect for hardware hacks. If you have a problem getting OMTI controllers, you can probably substitute one of many such (SCSI || SASI)/ST506 adapters available from a variety of manufacture, (most of which have gone bankrupt :*) ) PS I didn't get a chance to read the article, so I may be in error assuming that they use the SCSI adapter. -- "What is a DJ if he can't scratch?" - Uncle Jamms Army The views expressed are those of the author, and not of Visual Edge, nor Usenet. David Lai (vedge!lai@larry.mcrcim.mcgill.edu || ...watmath!onfcanim!vedge!lai)
papa@pollux.usc.edu (Marco Papa) (04/17/88)
In article <252@vedge.UUCP| lai@vedge.UUCP (David Lai) writes: |In article <938@unccvax.UUCP|, wdg@unccvax.UUCP (Doug Gullett) writes: || I am not familiar with OMTI-controllers. Could someone fill me in || about them. | |I think what they are referring to are SCSI to ST506 adapters manufactured |by OMTI. I'm not sure if OMTI is still in business or not but I have the |following number: | | SMS (don't know what it stands for) phone (415) 964-5700 | (I think they either manufacture the boards, or bought out | whoever used to). OMTI controllers are some of the BEST around. The original controllers that IBM was selling for the XT and AT were manufactured by OMTI. I just bought one for my BridgeCard from Sunnyvale Memories: 1-800-262-3475 (outside CA) 1-800-922-3475 (in CA) These are some of the prices: XT Controllers (fine for BridgeCard): OMTI 5520-10 MFM $65 OMTI 5227-10 RLL $85 AT Controllers: OMTI 8240 MFM $155 OMTI 8247 RLL $200 Sunnyvale memories will sell PC kits with one of the XT OMTI controllers and miniscribe 3.25 in disks from Miniscribe (8425 22M MFM, 8438 32M RLL). The 20M MFM kit is $320, the 32M RLL kit is $350. They are very knowlegebale about the Amiga and which hardware will work with BridgeCards etc. They have a 2 page ad in the latest Computer Shopper and Ted Drude article on Amiga Hard Disk recommends them. -- Marco -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= uucp:...!pollux!papa BIX:papa ARPAnet:pollux!papa@oberon.usc.edu "There's Alpha, Beta, Gamma and Diga!" -- Leo Schwab [quoting Rick Unland] -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
ggibeau@ucqais.uc.edu (George Gibeau) (04/21/88)
In article <252@vedge.UUCP>, lai@vedge.UUCP (David Lai) writes: > In article <938@unccvax.UUCP>, wdg@unccvax.UUCP (Doug Gullett) writes: > > I am not familiar with OMTI-controllers. Could someone fill me in > > about them. > > I think what they are referring to are SCSI to ST506 adapters manufactured > by OMTI. I'm not sure if OMTI is still in business or not but I have the > following number: > The reason that these kits use an OMTI controller is because the OMTI controllers write out any bad tracks on the hard drive to the controller cards ROM. The OMTI actually has a Zilog Z-80 co-processor on it. As you probably know, when AmyDos encounters a bad track on a disk, it throws up all over the place :-). Since most hard drives come from the factory with some sort of defect on them, they (IBM type DRIVES) could not be used with the Amiga Since the OMTI writes out the bad sectors, it sorta renumbers them so that it looks like a perfect drive to AmyDos. (IE. sector 5 is bad, it then renumbers all the following sectors by one less than the actual sector number until it encounters another bad sector, and so on. Then when you do a checkdisk or verify, it looks like a perfect disk -this is a very over simplified example, but you get the point.) There are two OMTI controllers that are available that will allow IBM drives to be used with the Amiga, one for MFM format, and one for RLL (RLL gets you 50% more disk space on RLL type drives, ie. 40 meg + RLL = 60 megs) Hope this helps a bit. George Gibeau Walking the fence between Amiga and IBM (hope the wind doesn't shift) -- (Define the Universe and give 3 examples.) Idiots? They're worse than idiots. They're bureaucrats!! UUCP: uccba!ucqais!ggibeau BBS: (513) 721-7977 GT NODE: 006/005 US Snail-Dept of Biology ML 06, University of Cincinnati, Ohio 45221
gregg@hechcx.HEC.HARRIS.COM (Gregg Asherman) (04/28/88)
Line eater The OMTI 5520 5527 controllers have the assign alternate track function that is what makes them different from some of the other controllers on the market. For the Amiga, an inexpensive hard disk controller can be constructed using the OMTI controllers and the MAX-hackers package available from palomax inc. in PA. The interface is very fast, the OMTI is the fastest most inexpensive controller that I have seen interfaced to an Amiga. You may use other controllers with this kit , but there may be unknown results so be wise, use the specified controller! MFM is MFM and RLL is RLL one controller will not jam any more data on a disk than another controller it was written in the previous article that with a 40 meg drive and an OMTI rll controller you could get 60 meg well, that simply is not logical . bye Gregg@hechcx
mph@rover.UUCP (Mark Huth) (04/30/88)
In article <519@hechcx.HEC.HARRIS.COM> gregg@hechcx.UUCP (Gregg Asherman) writes: > >MFM is MFM and RLL is RLL >one controller will not jam any more data on a disk than another controller > >it was written in the previous article that with a 40 meg drive >and an OMTI rll controller you could get 60 meg >well, that simply is not logical . Well, so much for logic. RLL controllers put 50% more data onto a given disk than MFM. MFM encoding essentially uses two baud per bit to ensure that the clock recovery circuits always have timing transitions to lock to. RLL uses an encoding where the length of successive 0s or 1s is limited so that the clock recovery circuits can maintain lock, but data is contained in nearly every baud. RLL stands for RunLengthLimited. For RLL to work well, the disk surface usaually has to be somewhat higher quality - hence a Seagate 238 is an RLL cetified 225. Mark Huth
lphillips@lpami.van-bc.UUCP (Larry Phillips) (05/02/88)
[please tell me if this line doesn't arrive at your site] In <519@hechcx.HEC.HARRIS.COM>, gregg@hechcx.HEC.HARRIS.COM (Gregg Asherman) writes: >MFM is MFM and RLL is RLL >one controller will not jam any more data on a disk than another controller >it was written in the previous article that with a 40 meg drive >and an OMTI rll controller you could get 60 meg >well, that simply is not logical . But it is logical. RLL is simply a different way of encoding the data that allows you to get 50% more data onto the disk. Example: A Seagate ST225 is a 20 meg drive... 4 heads, 613 cylinders, A Seagate ST238 is a 30 meg drive... 4 heads, 613 cylinders. They only differ in that the ST238 is 'RLL certified', and has been tested for its data integrity at the higher flux change rate. Normally, RLL drives use plated media and/or better heads to handle the density. An MFM drive that holds 40 megs can be formatted to 60 megs using an RLL controller, but it will tend to be unreliable, and often will start losing data in time (time being anywhere from minutes to weeks). Similarly, a 60 meg RLL drive can be formatted with an MFM controller, resulting in a 40 meg drive. Though this is more reliable, some manufacturers recommend not doing it. Seagate apparently goes so far as to say that using one type of drive with the other type of controller will void your warranty. Summary: The controller determines the amount of data on the drive. -larry -- Janus? Well, look at it this way. If you squint a little, the J could be Amiga checkmark, and the rest of the word describes MsDos. +----------------------------------------------------------------+ | // Larry Phillips | | \X/ {ihnp4!alberta!ubc-vision,uunet}!van-bc!lpami!lphillips | | COMPUSERVE: 76703,4322 | +----------------------------------------------------------------+