Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site cadovax.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!ihnp4!houxm!whuxl!whuxlm!akgua!sdcsvax!sdcrdcf!trwrb!trwrba!cadovax!keithd From: keithd@cadovax.UUCP (Keith Doyle) Newsgroups: net.micro.cpm Subject: Re: Dynamic Memory Message-ID: <440@cadovax.UUCP> Date: Fri, 8-Mar-85 16:17:55 EST Article-I.D.: cadovax.440 Posted: Fri Mar 8 16:17:55 1985 Date-Received: Sun, 10-Mar-85 07:48:01 EST References: <8809@brl-tgr.ARPA>, <523@intelca.UUCP> Organization: Contel Cado, Torrance, CA Lines: 32 [............] > I tried to install dynamic memory in my CompuPro system (8085/8088). The > board could be strapped for up to 8 wait states so I didn't think that > I would have any problems. I figured that in the worst case 8 wait states > would be alright since the memory was so cheap. Wrong! I put the memory > at 0000H and I couldn't get the 8085 to boot under CP/M since the disk > controller (DISK1) was too fast for the memory even with 8 wait states. > I put the memory above my RAM16's and tried to use the 8088 (CP/M86) > debugger to deposit values in the memory without any luck. The only way > I could get the memory to work was to run my 8085 at 2 MHZ with no wait > states. > > The lesson to be learned is that if you have a disk controller that > does DMA don't buy dynamic memory. > > Dennis [BRAKE@ARI-HQ1] I have a CompuPro Disk1 that I've been using with an ExpandoRam dynamic card for years! The only problem I've ever had with the dynamic RAM card was in conjunction with an el-cheapo Z-80 CPU card which I believe was solvable, but I decided to scratch the CPU card anyway. How fast is the RAM supposed to be? is it only 2 MHZ? I would think that the DMA speed would be somewhat governed by the rate it's coming off the disk which ain't that fast. Are you sure that speed is the problem? If by some chance the DMA is being clocked with the CPU's clock, maybe something can be done to use a divided by 2 clock for the DMA. However before attempting something like this, I'd make sure that you really have your finger on the problem. Keith Doyle # {ucbvax,ihnp4,decvax}!trwrb!cadovax!keithd "You'll PAY to know what you REALLY think!"