denbeste@spdcc.COM (Steven Den Beste) (01/12/90)
I bought a CSA Midget Racer last summer some time and put it in my 1000, and put a 68881 on it. It worked perfectly as long as there wasn't an oscillator installed in the Midget Racer; as a result, I've been having to run the 68881 at 7.16 MHZ. Just to clarify: It worked with the oscillator as long as my Starboard II (with my SCSI interface most of my RAM) wasn't hooked to my 1000, and it worked fine with the Starboard as long as the oscillator wasn't installed. Mandelvroom works at about the same speed in 68020 integer mode and in 7.16 MHZ 68881 mode. Rather underwhelming. To get it to work at all, I had to do the "PAL Grounding Mod". [At this time I'd like to say something: If there is an A1000 still in existence which hasn't had this fix done, its owner should get it done immediately.] I had pretty much resigned myself to a 7 MHZ 68881, even though it is a 16 MHZ part, until I read some of the discussions here recently about this problem. The last time I had called CSA they blamed the problem on Microbotics. Someone here said that they had changed their tune, so I called them again. The marketing guy I spoke to took my number and went to talk to their manufacturing guy. He then called me back and told me that my problem was probably a bad oscillator. (And he didn't even have any prospect of making another sale to me! Thanks a lot, guys!) To make it short, I went and bought another oscillator, and it has worked flawlessly. I have no idea what was wrong with the first one, but it may simply have been generating an ugly signal. ...best $7.95 I've spent in a long time. Folks, Turbo-Silver SV really screams with a 16 MHZ 68881! I kind of wish I had bought an even faster chip, now. [Yes, I know I could probably make the part I have run at about 18 MHZ, but I've had enough bus problems to last my life, and I don't want to take any more chances.] On to another issue. I originally understood that there were two versions of the standard floating point loadable-library, one done in software and one which used the 68881. When you installed a floating point chip in your system, you replaced the library, and all the programs which used floating point would now use the 68881. Was I misinformed? Just where do I get this new library? Or does the standard library have a check-and-branch based on presence of the 68881 already?
barrett@jhunix.HCF.JHU.EDU (Dan Barrett) (01/13/90)
In article <1212@ursa-major.SPDCC.COM> denbeste@ursa-major.spdcc.COM (Steven Den Beste) writes: >To get it to work at all, I had to do the "PAL Grounding Mod". [At this time >I'd like to say something: If there is an A1000 still in existence which >hasn't had this fix done, its owner should get it done immediately.] Why? I have 2 devices on my expansion bus with no problems. (C.Ltd. SCSI and Starboard II.) Dan //////////////////////////////////////\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ | Dan Barrett, Department of Computer Science Baltimore, MD 21218 | | INTERNET: barrett@cs.jhu.edu | | | COMPUSERVE: >internet:barrett@cs.jhu.edu | UUCP: barrett@jhunix.UUCP | \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\/////////////////////////////////////
ridder@elvira.enet.dec.com (Hans Ridder) (01/13/90)
In article <1212@ursa-major.SPDCC.COM> denbeste@ursa-major.spdcc.COM (Steven Den Beste) writes: >To get it to work at all, I had to do the "PAL Grounding Mod". [At this time >I'd like to say something: If there is an A1000 still in existence which >hasn't had this fix done, its owner should get it done immediately.] My A1000 is working perfectly (without the grounding mod.), you want me to take a soldering iron to it? Nooooo waaaaaay! You might actually scare some folks into doing it for no reason. Ever heard about sleeping dogs? >...[Yes, I know I could probably make the part I have run at about 18 >MHZ, but I've had enough bus problems to last my life, and I don't >want to take any more chances.] Oh, I guess you have... -hans ======================================================================== Hans-Gabriel Ridder Digital Equipment Corporation ridder@elvira.enet.dec.com Customer Support Center ...decwrl!elvira.enet!ridder Colorado Springs, CO