Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!cs.utexas.edu!samsung!uunet!aplcen!haven!decuac!decatl!bacchus.pa.dec.com!granite.pa.dec.com!mwm From: mwm@raven.pa.dec.com (Mike (Real Amigas have keyboard garages) Meyer) Newsgroups: comp.sys.amiga Subject: Re: Real System Comparisons Message-ID: Date: 8 Aug 90 14:51:28 GMT References: <13466@cbmvax.commodore.com> <13678@cbmvax.commodore.com> <40@faatcrl.UUCP> Sender: news@wrl.dec.com (News) Distribution: usa Organization: Missionaria Phonibalonica Lines: 51 In-Reply-To: jimb@faatcrl.UUCP's message of 8 Aug 90 05:15:27 GMT daveh@cbmvax.commodore.com (Dave Haynie) writes: >>While I'm willing to accept those as substitutes for each other, there >>are still some people who think that SCSI doesn't belong in a "real >>computer." >Considering that [a] SCSI is significantly faster than EDSI (5 MB/s for >SCSI-1 vs. 1.5 MB/s for EDSI), and that [b] SCSI is the de-facto hard >disk standard in every Amiga, Mac, NeXT, and a whole slew of Workstation >class machines like Suns, I can only wonder what "real computers" are >using these days. Well, I went and asked those same people. The general tone of the answer was: We see at best 1.5 MB/sec out of async. Get twice that out of sync, and you might have something worth using. As for what these people are using, those Sun workstations generally talk to Sun servers with a pair of wren's, each wren on it's own controller. Having that second controller makes the difference between a sluggish server and a reasonable one. Adding something like the Legatto disk accelerator into the system can begin to make even SunOS 4 seem useable. Such systems (parallel disk paths to the backplane) have been the norm for Unix systems for over a decade. You might note that the ESDI controllers on these systems (and on many of the 486s I saw advertised) have lots of on-controller cache, allowing for full-track reads onto the controller, which along with a modern file system gives most of that 1.5MB/sec in actual throughput. On the other hand, the best I've seen quoted for actual SCSI throughput to the file system is 1.9MB/sec. As for "real computers", most of those people are coming from large systems backgrounds, where arranging to get disk data to a a hundred users (or more) is the norm, not providing blocks for the person sitting in front of the workstation. The way you view almost any component of a system (including documentation and maintenance) is radically different when you move from multiuser systems to workstations. I expect most of these people will catch up with the real world before to long. Of course, it'd also be nice if the workstation people could bring some of their components up to level acceptable for multiuser systems.