Path: utzoo!attcan!uunet!snorkelwacker!tut.cis.ohio-state.edu!ucsd!hub.ucsb.edu!lemon!dz From: dz@lemon.ucsb.edu (Daniel James Zerkle) Newsgroups: comp.sys.amiga.hardware Subject: Re: Amiga-Sun unix question Message-ID: <5777@hub.ucsb.edu> Date: 12 Jun 90 01:08:49 GMT References: <2029@mindlink.UUCP> <12477@cbmvax.commodore.com> Sender: news@hub.ucsb.edu Reply-To: dz@lemon.UUCP (Daniel James Zerkle) Organization: University of California, Santa Barbara Lines: 84 In article <12477@cbmvax.commodore.com> jesup@cbmvax (Randell Jesup) writes: > > Our SysVR4 Unix will support both X and OpenLook (on top of X I think), >so it should work. (No Suntools, of course.) Wonderful! Is this official? >I think X works in 4MB, but >OpenLook may require more than 4MB ram to work well. THe unix guys could >answer more precisely. Being a "Unix Guy", I pity the fool who tries to run ANY windowing environment, and expecially X, in less than 8 megabytes on UNIX. You CAN do it in 4 (I've seen it happen). However, when our lab of Suns went from 4 megs to 8, the improvement was spectacular. In 4 megs, you will spend all of your time paging (I've done some tests). Multi-user is hopeless. Two medium-sized or one large application really make performance go down the tubes. Remember that SYSVR4 is going to have a HUGE kernel, since it includes both the Berkeley and AT&T stuff. Although 8 megabytes is much better, 12 still makes a significant improvement. Unfortunately, I have never seen two similar machines running X with 8 and 12 megs, I have heard about performance improvements on another platform -- the NeXT. That runs a windowing environment over a Unix-like operating system (Mach). People who upgrade from 8 to 12 megs say the performance increase is wonderful, especially in starting up large applications. I don't know about OpenLook, but as it is a huge application that runs on top of X, I would add memory appropriately. Also, remember that if you get Unix, you will need high performance disk storage. EVERYTHING that Unix does requires an access to the disk. What's more, the virtual memory system swaps and pages memory that has not been used lately to the disk drive. After you copy all of the Unix operating system files onto your disk (don't even THINK of running Unis from floppy-- you can't), you will need a good chunk of spare space (say, 20 megs) for swap and page space--the more the better. Of course, this is in addition to your normal Amiga files. Generally, the speed of the system is dependent on the speed of your disk. Of course, CPU speed is important, too, especially for mathematical applications. However, I cringe at the thought of Unix running on a slow disk with not enough RAM. Actually, I cringe at the memory of doing this. Anyway- Here's a summary of performance effects from most to least important: 1. RAM space: 4 megs to run, 8 megs to run decently, 12 megs to run well. Especially on a windowing Sys 5 release 4 system. 2. Disk space: Probably need 100 megs for full system, plus swap, plus user files, plus applications files, plus programming libraries, plus.... We use 600 meg drives at work for Sun 3/60's, but this is overkill. The NeXT does very well with 330 meg drives, but that comes with a slew of software you won't need. 3. Disk speed: Faster the better. Figure < 30 ms if you don't want the system to act like molasses in winter. < 15 ms is positively zippy. A 32-bit bus really helps here to keep the data moving. 4. CPU speed: A 12 mHz 68020 is just fine if you don't do any heavy number crunching. Actually, I don't know if 68020's go at 12 mHz, but I know they go at 16. You could slow one of those down :). I don't think Amiga Unix will run on less than a 68020. 5. Network throughput: This only counts if you are using your system as a client on a network so you can get files from someone else's disk. Bandwidth on ethernet is so high that you will have to worry more about whether the disk serving all the clients can deal with it. Figure 1 server per six machines, if all machines are in use at once. Naturally, bigger and faster disks can handle more clients. Well, I got way off the topic. I hope you find this useful, and not too discouraging. Of course, the numbers I'm talking about are for optimum performance. You may get the system to WORK with less. You will just be able to do much better. Just don't try to do anything on Unix with less than 4 megabytes or RAM, or people will laugh at you. And if you want the system to go faster, spend the cash on RAM first, then spend it on the other stuff. | Dan Zerkle home:(805) 968-4683 work:687-0110 | | dz@cornu.ucsb.edu dz%cornu@ucsbuxa.bitnet ...ucbvax!hub!cornu!dz | | Snailmail: 6681 Berkshire Terrace #5, Isla Vista, CA 93117 | | Disclaimer: My fish are stupid. |