tim@hoptoad.uucp (Tim Maroney) (10/15/88)
It seems to me that with 8 Megs standard main memory, you shouldn't need to touch the disk very often at all for most applications. Multi-user databases seem like the most troublesome applications in this respect. For almost everything else, just cache the entire file in RAM after doing a sequential (front-to-back) transfer into memory. Not too many seeks in that kind of operation, at least until the disk becomes fragmented. On thge other hand, page fault handling seems destined to be slow, unless the head spends all its idle time in the page swapping area automatically. I think the optical disk drive speed is probably quite liveable, especially with every compute-bound task screaming away on the 25MHz 68030! As pointed out, what's missing has been discussion of the external interfaces. How many serial ports? Any parallel ports? Serial ports capable of LocalTalk (nee Appletalk)? Built-in Ethernet interface like the Suns it's being compared to? Everyone says it has NFS, but that's a higher protocol level than I'm concerned about. How well does it interface to the outside? -- Tim Maroney, Consultant, Eclectic Software, sun!hoptoad!tim "In any religion or form of worship, followers should be allowed to think for themselves. In every religion that has a god other than Jesus Christ, adherents are not allowed to think for themselves." -- Lauren Stratford, "Satan's Underground"
jbs@fenchurch.MIT.EDU (Jeff Siegal) (10/15/88)
In article <5632@hoptoad.uucp> tim@hoptoad.UUCP (Tim Maroney) writes: >It seems to me that with 8 Megs standard main memory, [...] >just cache the entire file in RAM [...] It is important to note that Mach does this automatically. The Mach group claims a significant reduction in I/O operations over 4.3 BSD when "compiling a subset of programs in /bin" >On thge other hand, page fault handling seems destined to be slow, unless the >head spends all its idle time in the page swapping area automatically. Mach doesn't have a designated swapping area like Unix does. It just swaps directly to the user filesystem (taking blocks away only when needed). An interesting question is what strategy it uses to select blocks (i.e. layout) for this purpose. Anyway, as others have already pointed out, it probably isn't going to page much with 8MB standard memory. Jeff Siegal
yap@hammer.me.toronto.edu () (10/16/88)
>Anyway, as others have already pointed out, it probably isn't going to >page much with 8MB standard memory. > >Jeff Siegal 8MB is DICK-ALL!!! If you're going to do any extensive symbolic math with Mathematica, you'll need all you can get. I've run out of memory using Macsyma on a Sun 3/180 with 24MB of usable memory (real + virtual), admittedly the gist of the problem lies with Macsyma's inability to do garbage collection correctly on the Sun (at least with the version of Macsyma we're using). However, this doesn't detract from the fact that you need gobs of real plus sloooow virtual memory to do anything useful. I'd be (pleasantly) surprised if Mathematica worked well (<-- fast) with less memory. Perhaps I'm ignorant, at least I'm happy, Davin. -- Davin Yap, Dept. of Mech. Eng., U of Toronto, Toronto, CANADA, M5S 1A4 Work: (416)978-6443 ,Email addresses in order of fastest to slowest: (1) utme!yap@utorgpu.bitnet (2) yap@me.toronto.edu (3) uunet!utai!utme!yap
henry@utzoo.uucp (Henry Spencer) (10/16/88)
In article <10284@eddie.MIT.EDU> jbs@fenchurch.MIT.EDU (Jeff Siegal) writes: >Anyway, as others have already pointed out, it probably isn't going to >page much with 8MB standard memory. You forgot, it comes with GNU software. That means it *will* page with 8MB standard memory! -- The meek can have the Earth; | Henry Spencer at U of Toronto Zoology the rest of us have other plans.|uunet!attcan!utzoo!henry henry@zoo.toronto.edu
jbs@fenchurch.MIT.EDU (Jeff Siegal) (10/17/88)
In article <1988Oct16.041207.718@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes: >You forgot, it comes with GNU software. That means it *will* page with >8MB standard memory! You forgot the ":-)". Really. I use GNU software all the time, on a 5 or 6MB machine, without paging (well, maybe a little, but nothing noticeable). GNU Emacs wants about 1MB and GCC wants 1-2MB when compiling non-trivial code. Also, GCC generates code that is as small or smaller than most other compilers (although I have no idea what the Objective-C preprocessor generates). We'll have to wait and see, I guess. Jeff Siegal
mvs@meccsd.MECC.MN.ORG (Michael V. Stein) (10/17/88)
In article <1988Oct16.041207.718@utzoo.uucp: henry@utzoo.uucp (Henry Spencer) writes: :In article <10284@eddie.MIT.EDU: jbs@fenchurch.MIT.EDU (Jeff Siegal) writes: ::Anyway, as others have already pointed out, it probably isn't going to ::page much with 8MB standard memory. : :You forgot, it comes with GNU software. That means it *will* page with :8MB standard memory! What GNU software? -- Michael V. Stein - Minnesota Educational Computing Corp. - Technical Services {bungia,uiucdcs,umn-cs}!meccts!mvs or mvs@mecc.MN.ORG
henry@utzoo.uucp (Henry Spencer) (10/25/88)
In article <10288@eddie.MIT.EDU> jbs@fenchurch.MIT.EDU (Jeff Siegal) writes: >>You forgot, it comes with GNU software. That means it *will* page with >>8MB standard memory! > >You forgot the ":-)". Really. I use GNU software all the time, on a >5 or 6MB machine, without paging (well, maybe a little, but nothing >noticeable). GNU Emacs wants about 1MB and GCC wants 1-2MB when >compiling non-trivial code. No, I didn't forget the ":-)". Really. Friends of mine who have used GCC for production work quoted numbers an order of magnitude larger. -- The dream *IS* alive... | Henry Spencer at U of Toronto Zoology but not at NASA. |uunet!attcan!utzoo!henry henry@zoo.toronto.edu
jmunkki@kampi.hut.fi (Juri Munkki) (10/25/88)
In article <11432.1988Oct15.23:26:16@hammer.me.toronto.edu> yap@hammer.me.UUCP writes: >I'd be (pleasantly) surprised if Mathematica worked well (<-- fast) with >less memory. Mathematica "works" on a Mac II with 2 MB RAM and _you_ can do work with 5MB. I guess 8MB should be ok. You are eventually going to find a way to run out of memory (probably isn't too hard), but then you'll still have plenty of virtual memory before you run out. _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._ | Juri Munkki jmunkki@hut.fi jmunkki@fingate.bitnet I Want Ne | | Helsinki University of Technology Computing Centre My Own XT | ~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~