Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!masscomp!ocpt!princeton!njin!spcvxb.spc.edu!terry From: terry@spcvxb.spc.edu (Terry Kennedy, Operations Mgr.) Newsgroups: comp.sys.dec Subject: Re: RQDX[123] differences Message-ID: <1991Jun26.033940.1531@spcvxb.spc.edu> Date: 26 Jun 91 03:39:40 GMT References: Organization: St. Peter's College, US Lines: 35 In article , deraadt@cpsc.ucalgary.ca (Theo de Raadt) writes: > Ok, so I see from some old postings that you can hook MFM disks up to > RQDX3 controllers. What are the differences between these controllers > (I mean, are they all MFM?). Yes, they're all MFM. Assuming you have the latest ROMs in each, the RQDX1 supports RD51, RD52, RX50. The RQDX2 adds RD53. The RQDX3 adds RD54, RX33, RD31, RD32, RD33 (which I believe was not marketed). The RQDX1 and 2 are essentially the same board - the RQDX1 is an M8639-YA and the RQDX2 is an M8639-YB (I guess the -00 was a total loss 8-). The 2 is just a newer circuit layout to attempt to correct the bus problems in the 1. You can put RQDX2 ROMs in the 1 and run RD53's. The 1 and the 2 are both 3/1 interleave. The RQDX3 is a dual-wide board (M7555) which was done with purchased technology to fix the performance issues and the high manufacturing cost of the 1 and 2. It's more intelligent, does 1/1 interleave, and can (if you whisper the right sweet nothings in its ear 8-) be convinced to handle non-DEC disks. For reference: RX33 - Teac FD-55GFR RX50 - A DEC-built oddity RD31 - Seagate ST225 RD32 - Seagate ST241-1 RD51 - Seagate ST-412 RD52 - Quantum Q540 / Atasi 3046 / [almost] Evotek ET-5540 RD53 - Micropolis 1325 with jumper R7 inserted (1335 also works) RD54 - Maxtor XT-2190 Terry Kennedy Operations Manager, Academic Computing terry@spcvxa.bitnet St. Peter's College, US terry@spcvxa.spc.edu (201) 915-9381