Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!elroy.jpl.nasa.gov!jato!hanauma.jpl.nasa.gov!hyc From: hyc@hanauma.jpl.nasa.gov (Howard Chu) Newsgroups: comp.sys.atari.st.tech Subject: Re: Hardware Project: RAM disk Message-ID: <1991Jun13.232233.26892@jato.jpl.nasa.gov> Date: 13 Jun 91 23:22:33 GMT References: <676362150.57@egsgate.FidoNet.Org> Sender: nobody@jato.jpl.nasa.gov Organization: SAR Systems Development and Processing, JPL Lines: 70 Nntp-Posting-Host: hanauma.jpl.nasa.gov In article <676362150.57@egsgate.FidoNet.Org> Matthew.Baker@f98.n250.z1.FidoNet.Org (Matthew Baker) writes: >From article , by es2a+@andrew.cmu.edu >(Eric Stuyvesant): >> I've been considering building some sort of RAM disk for my 4 Mb >> 1040STE, and was wondering if anyone else out there would be similarly >> interested... >If it works, I might build one (huge :) Well, since I already have a 4MB cartridge port drive from Alpha Systems, yeah, it has to be much larger to be interesting... >> Necessary components of said RAM disk: >> * use of SIMMs >- SIPs would result in a slightly cheaper device. Use machine pin socket >strip >instead of $IMM $ocket$ >> * support of at least 2 Mb in a minimum construction >> * support for different sized SIMMs (256K, 1Meg, 4Meg) >> * as cheap as possible Reasonable... >-A major hassle with _anything_ using DRAMS is the refresh timing. The >TI 746301 is the only DRAM controller I have had much experience with, and >that was extremely frustrating. Hence I use SRAMS in all my projects. :) Sounds nice, but that increases the base cost quite a bit, eh? >> * Cartridge port interface, similar to the Alpha Systems RAMdisk. This >> has the disadvantage of being slow, and very non-portable to non-ST >> systems. >Not necessarily slow, but inconvenient. Means a large box stuck to the side >of >the machine. Yeah, that has certain drawbacks, particularly when working with limited physical desktop space... But now I've got it all hidden inside a tower case, standing next to the desk... >> * Serial interface, possibly with a native CPU. This would definitely >> be slow, even at 19200, but would be supremely portable to non-ST >> systems. Why bother building a solid-state disk only to slow it down behind a silly *serial* interface? Remember 8-bit Ataris? 5-1/4" floppy drives using SIO at a blazing 19200bps?? If you want to drop to that speed, just get some Old Old Old hard drives, you don't need to waste bucks on DRAMs... You could consider the parallel port; it's bidirectional, and most new PC clones also have bidirectional ports now. (If portability is a big issue...) Not sure what the top speed is for that though, I think it's only around 1000cps, which is only slightly faster than a 9600bps serial port... >> * SCSI interface, possibly with a native CPU. I imagine that this >> would be rather expensive to build, due to the cost of SCSI chipsets and >> an ACSI->SCSI converter board. It would, however, be useful on non-ST >> systems. Throughput would probably be not bad. >Native CPU more or less essential, (68000 series (eg 010, 070) weould be >good) >The NCR 5380 - SCSI chip, is not very expensive. Easy to talk to as well. Wanna be even *more* clever... Use SRAM, as suggested, mounted on a removable carrier. Battery on-board the cartridge, of course. That would be really slick... -- -- Howard Chu @ Jet Propulsion Laboratory, Pasadena, CA Disclaimer: How would I know, I just got here!