From: Heiko Z. <hz...@pr...> - 2003-07-23 12:23:36
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Morning! it's early, but I try to answer your questions. On 07/23/2003 03:03:27 AM Walter Haidinger wrote: >Well, while this a good idea at first sight, it also has some drawback= s. >To name but a few: >* Speed >On a slow (read old) machine this may be an issue. While performance >from ramdisk _may_ be acceptable (imagine an old 486, not even Pentium= ), >the access time imposed by the CD-Rom _would_ render such a system >almost useless. I expect that thing will be faster on those machines. Before we had to unpack the ramdisk content and the packages, which took quite a while o= n old machines. When all the stuff is on CD, the binary can be accessed immediately, si= nce the CD is already spinning during bootup. >* Reliability >I doubt that neither CD-Roms nor CDs are built to spin 24/7 >unlike hard- or even ramdisks! ;-) I was scared about that too, but it's not a problem. Once the system is booted up, it rarely accesses the CD. Most CD access= is necessary when you're logged in to the console and do something. When t= he DL box is just running, it should rarely access the CD. We already did some testing and it looks like it works out this way. >* If you boot from net and provide the DL ISO by NFS, you cannot >unmount once DL is up. You couldn't unmount before either. We hade a few things on CD which ma= de it impossible to unmount it once DL was running. >Therefore a simple question: >Will the utilization of the CD optional, i.e. will DL still be able to= >extract to a ramdisk as "usual" ? >If so, will this be a configurable option? Actually no. I was thinking about this but it would add an extreme over= head to the CD and our build system. >I'm asking this because I'm running DL on machines with low memory (16= >to >32MB) and extract to harddisk (a mke2fs during boot to clean up doesn'= t >take that long) which replaces the ramdisk. When everything works out, you should be able to use the standard DL at= least on the 32 MB machines. 16 MB is a taff goal, but let's see how it is once we're finished with = the changes. We should soon ( 1 week or so) have a test version available, then you = can take a look at it. cya Heiko = |
From: Heiko Z. <hz...@pr...> - 2003-07-23 12:24:55
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On 07/23/2003 03:10:08 AM Mats Liljegren wrote: >Hi, > >About this discussion to read from CD. Would a read-only filesystem >residing >in RAM (I think there is such a filesystem available for Linux in the >kernel >distribution) be nearly as good as running from CD? > >I'm also thinking about booting from a file server. Yes it should. You just need lot's of RAM. But when you use our build system and create your own ISO, then you can= control the size of it. Heiko = |
From: Walter H. <wal...@gm...> - 2003-07-23 14:14:29
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On Wed, 23 Jul 2003, Heiko Zuerker wrote: > Morning! > > it's early, but I try to answer your questions. Thanks! 'Early' varies depending on your location on the globe... ;-) > >* Speed > >On a slow (read old) machine this may be an issue. While performance > >from ramdisk _may_ be acceptable (imagine an old 486, not even Pentium), > >the access time imposed by the CD-Rom _would_ render such a system > >almost useless. > > I expect that thing will be faster on those machines. Before we had to > unpack the ramdisk content and the packages, which took quite a while on > old machines. Yes, this was because the packages were compressed which never made any sense to me. I'm _not_ talking about compressing the DL distribution tarball, of course! > When all the stuff is on CD, the binary can be accessed immediately, since > the CD is already spinning during bootup. True. However, I meant _after_ boot when you're logged in. > >* Reliability > >I doubt that neither CD-Roms nor CDs are built to spin 24/7 > >unlike hard- or even ramdisks! ;-) > > I was scared about that too, but it's not a problem. > Once the system is booted up, it rarely accesses the CD. Most CD access is > necessary when you're logged in to the console and do something. When the > DL box is just running, it should rarely access the CD. Right, that's what I'd expect too. Fortunately we could agree that being logged in isn't the default mode of operation. So working off CD while being logged in is OK, IMHO. > >* If you boot from net and provide the DL ISO by NFS, you cannot > >unmount once DL is up. > > You couldn't unmount before either. We hade a few things on CD which made > it impossible to unmount it once DL was running. Possible. Never noticed because I don't use DL with physical CDs, only loopback-mounted images which I did not bother to umount. > Actually no. I was thinking about this but it would add an extreme overhead > to the CD and our build system. Ok, then I'll stick to loopback-mounting I guess. On second thought, reading from CD is actually a good idea as the advantages outweigh. > We should soon ( 1 week or so) have a test version available, then you can > take a look at it. Good! Thanks for your answers. Regards, Walter |