russell@muddcs.UUCP (08/03/84)
[plplplplplplplplplplplplplplplplplplplplplplplplplplplplplplplplplplp] I was wondering if anyone has a RAM disk for 4.2 BSD running on a VAX 750. We have 5 Meg, so there is plenty to go around. I'd thought we could put /tmp on the RAM disk to save a little time (and disk head wear) on compiles, etc. Any experience with this sort of thing out there ?? -- Russell Shilling {allegra,ihnp4,seismo}!scgvaxd!muddcs ===== ===== To: wade@nmtvax.UUCP Subject: Re: AD&D PBM GAME: WE'RE STILL HERE, READ IF YOU STILL WANT TO PLAY. In-reply-to: your article <433@nmtvax.UUCP> [==================] Wade, I'd like you to consider allowing me to play.
kermit@BRL-VGR.ARPA (08/10/84)
From: Chuck Kennedy <kermit@BRL-VGR.ARPA> We have two RAM disks on our 4.2BSD systems, one connected to a VAX 780, the other connected to a VAX 750. The RAM disks (which we call Bulk MOS units) are DATARAM BS-202 units. We originally bought some of these units to help out our PDP-11/70 systems which benefited greatly. We've had pretty good luck with the units as far as reliability, etc. Now for the bad news. The Bulk MOS units don't seem to be worth the effort for large virtual memory machines. They are not cost-effective when considered against the choice of buying another dedicated disk for /tmp space. There is some performance improvement from using the Bulk MOS since there is no rotational latency and no seek penalty. However, for the cost of a Bulk MOS unit, you can easily buy a dedicated Eagle drive and it's own controller. I certainly would not worry about disk head wear. Good luck, -Chuck Kennedy
mike@BRL-TGR.ARPA (08/16/84)
From: Mike Muuss <mike@BRL-TGR.ARPA> BRL has 2 VAX systems with RAM disks, on is a 780, the other a 750, both running 4.2 BSD. We use the Dataram BULK MOS product, which emulates an RF-11 head-per-track disk; we did the driver ourselves (it's availible). Advantages: No head motion for /tmp Disadvantages: The UNIBUS is busy enough without this stuff too. Transfer rates are generally less than what a MASSBUS device could do. Given the cost of the bulk mos device, you are better off buying more moving head disk drives and putting /tmp & some archival stuff out there (assuming you add MASSBUS disks). Best, -Mike Muuss (301)-278-6678 AV 283-6678 FTS 939-6678 ArpaNet: Mike @ BRL UUCP: ...!{decvax,cbosgd}!brl-bmd!mike Postal: Mike Muuss Leader, Advanced Computer Systems Team Computer Techniques and Analysis Branch Systems Engineering and Concepts Analysis Division U.S. Army Ballistic Research Laboratory Attn: DRXBR-SECAD (Muuss) APG, MD 21005