Odd OS X failure mode

Discussion in 'NZ Computing' started by Lawrence D'Oliveiro, Aug 14, 2007.

  1. I have a client who's reported an odd problem on one of his Macs running OS
    X. Apparently instead of booting up to the normal GUI, it's only presenting
    a Darwin console login screen.

    I don't have much experience of OS X, but I've never heard of Macs doing
    this sort of thing. With the older MacOS, if you didn't get the GUI, it was
    because the machine was failing to boot altogether.

    If this was a Linux box, I'd say the X server failed to start, possibly
    because of a driver or configuration problem, or (in the couple of cases
    where it actually happened to my clients) the partition containing the /tmp
    directory getting full. But since OS X doesn't (normally) run an X server,
    I don't know if similar considerations apply.

    Thoughts, anyone?
     
    Lawrence D'Oliveiro, Aug 14, 2007
    #1
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  2. Lawrence D'Oliveiro

    Hank Guest

    >
    > Thoughts, anyone?


    Replace it with a windows machine.
     
    Hank, Aug 14, 2007
    #2
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  3. Lawrence D'Oliveiro

    David Empson Guest

    Lawrence D'Oliveiro <_zealand> wrote:

    > I have a client who's reported an odd problem on one of his Macs running OS
    > X. Apparently instead of booting up to the normal GUI, it's only presenting
    > a Darwin console login screen.


    Does the startup sequence look normal prior to this point?

    It should do the startup chime, show a grey background with dark grey
    Apple logo, spinning activity indicator, then go to a blue screen with
    startup progress information (sometimes skipped if the computer is fast
    enough) before getting to the login prompt.

    There is a method of deliberately getting a console login screen if you
    type in the right incantantion at the login prompt (assuming you have it
    set to ask for a username and password, rather than a clickable list of
    users, or automatically logging on as a particular user).

    There is also a "single user" mode which you can get to by holding down
    the right key combination at startup. This gives you a root shell and
    doesn't ask for any passwords. (There are additional security mechanisms
    to prevent access to this without a password, if you are worried about
    physical security of the computer.)

    It doesn't sound like single user mode, so my guess is that something is
    causing it to go straight to the console login prompt.

    If I do this deliberately (by entering ">console" as the user name on
    the GUI login screen), I get a black screen with white text which says:

    Darwin/BSD (name-of-computer.local) (console)

    login:

    At this point, if I enter an incorrect user name and password once, it
    drops me back out to the GUI login window. If I enter a correct user
    name and password it gives me a shell prompt.

    Have they tried entering their user name and password? If it at least
    gets a shell prompt there is a chance of being able to investigate
    further and fix it.

    > I don't have much experience of OS X, but I've never heard of Macs doing
    > this sort of thing.


    Me either, and I do Mac technical support for a reasonable number of
    people.

    > With the older MacOS, if you didn't get the GUI, it was
    > because the machine was failing to boot altogether.
    >
    > If this was a Linux box, I'd say the X server failed to start, possibly
    > because of a driver or configuration problem, or (in the couple of cases
    > where it actually happened to my clients) the partition containing the /tmp
    > directory getting full. But since OS X doesn't (normally) run an X server,
    > I don't know if similar considerations apply.
    >
    > Thoughts, anyone?


    A possibly useful trick would be to start up the comptuer in Verbose
    mode, which will remain in text mode for the startup sequence (until it
    gets to the login window or prompt). This might reveal some clues about
    the problem, e.g. it might show an error message.

    To start up in verbose mode, hold down the Command-V key combination
    (Command is key with the Apple and Propellor symbols, to the left of the
    space bar) immediately after the startup chime, and keep holding them
    down until you get the text screen showing the details of the boot
    sequence.

    Most of it is gobbledigook to the average user but it should be
    intelligible to someone familar with Unix-a-like systems.


    I suspect the problem will be a corrupted preference file for
    loginwindow, or some component of the system has become damaged,
    resulting in it not being able to launch the loginwindow application,
    forcing it to revert to a console login.

    It might also be a fallback feature due to the automatic login account
    being damaged in some way which prevents login from occurring.

    This might be fixable by locating the damaged file, but it may be easier
    to do a system reinstall (using the "Archive and Install" method, which
    preserves user accounts and as much third party software as possible).

    I suggest you e-mail me directly for further discussion.
    --
    David Empson
     
    David Empson, Aug 14, 2007
    #3
  4. In message <1i2u6tq.1b2id0l104oabvN%>, David Empson
    wrote:

    [lots of detailed advice]

    Thanks for that info. I was with the client today, discussing other things,
    and he didn't mention the problem, so he must have got it resolved, perhaps
    by contacting his usual OS X support people.

    I must admit I was amazed at your description of all those cryptic key
    combinations to get into single-user mode, verbose mode and so on. It seems
    so much simpler on a Linux system. :)
     
    Lawrence D'Oliveiro, Aug 14, 2007
    #4
  5. Lawrence D'Oliveiro

    whoisthis Guest

    In article <f9qpd6$9p6$>,
    Lawrence D'Oliveiro <_zealand> wrote:

    > I have a client who's reported an odd problem on one of his Macs running OS
    > X. Apparently instead of booting up to the normal GUI, it's only presenting
    > a Darwin console login screen.
    >
    > I don't have much experience of OS X, but I've never heard of Macs doing
    > this sort of thing. With the older MacOS, if you didn't get the GUI, it was
    > because the machine was failing to boot altogether.
    >
    > If this was a Linux box, I'd say the X server failed to start, possibly
    > because of a driver or configuration problem, or (in the couple of cases
    > where it actually happened to my clients) the partition containing the /tmp
    > directory getting full. But since OS X doesn't (normally) run an X server,
    > I don't know if similar considerations apply.
    >
    > Thoughts, anyone?


    Probably has gone into it open-firmware mode.
    You can get this by holding down Command-option-o-f

    When you are in this mode type
    reset-nvram
    reset-all

    This resets the pram and reboots the machine, all should be good again.
     
    whoisthis, Aug 14, 2007
    #5
  6. Lawrence D'Oliveiro

    whoisthis Guest

    In article <>,
    Hank <> wrote:

    > >
    > > Thoughts, anyone?

    >
    > Replace it with a windows machine.


    See.... when you don't specify INTELLIGENT thoughts, all sorts of idiots
    come out of the woodwork thinking they are funny.
     
    whoisthis, Aug 14, 2007
    #6
  7. Lawrence D'Oliveiro

    Bobs Guest

    Lawrence D'Oliveiro wrote:
    > I have a client who's reported an odd problem on one of his Macs running OS
    > X. Apparently instead of booting up to the normal GUI, it's only presenting
    > a Darwin console login screen.
    >
    > I don't have much experience of OS X, but I've never heard of Macs doing
    > this sort of thing. With the older MacOS, if you didn't get the GUI, it was
    > because the machine was failing to boot altogether.
    >
    > If this was a Linux box, I'd say the X server failed to start, possibly
    > because of a driver or configuration problem, or (in the couple of cases
    > where it actually happened to my clients) the partition containing the /tmp
    > directory getting full. But since OS X doesn't (normally) run an X server,
    > I don't know if similar considerations apply.
    >
    > Thoughts, anyone?



    Had a Windows 2000 box running for 7 years with no problems and not one
    crash. Buy a real OS.

    Thanks for coming.
     
    Bobs, Aug 14, 2007
    #7
  8. Lawrence D'Oliveiro

    David Empson Guest

    Lawrence D'Oliveiro <_zealand> wrote:

    > I must admit I was amazed at your description of all those cryptic key
    > combinations to get into single-user mode, verbose mode and so on.


    That's nothing. There are a lot more of them. :)

    Mostly to do with overriding the normal startup disk and booting from
    somewhere else, or going into a special mode.

    My favourite is the 'T' key, which puts a Mac into Firewire target mode.
    It then acts like a Firewire hard drive which can be connected to
    another computer. Great for copying lots of files, or to repair the
    internal hard drive, or to boot one computer from another's internal
    drive, or to migrate the entire system over to a new computer (which Mac
    OS X offers to do during the initial setup of a new computer).

    > It seems so much simpler on a Linux system. :)


    I expect most Linux systems would normally start up in the equivalent of
    Mac OS X's verbose mode. (My IPCop installation spits out pages of
    status messages on the console while starting up.)

    The Mac's policy has always been to have the normal startup sequence a
    clean and largely icon or picture-based experience, avoiding excessive
    use of text and technical terms, except if something goes wrong.

    --
    David Empson
     
    David Empson, Aug 14, 2007
    #8
  9. In message <1i2v3i5.bicjda7f15b1N%>, David Empson
    wrote:

    > Lawrence D'Oliveiro <_zealand> wrote:
    >
    >> I must admit I was amazed at your description of all those cryptic key
    >> combinations to get into single-user mode, verbose mode and so on.

    >
    > That's nothing. There are a lot more of them. :)
    >
    > Mostly to do with overriding the normal startup disk and booting from
    > somewhere else, or going into a special mode.
    >
    > My favourite is the 'T' key, which puts a Mac into Firewire target mode.
    > It then acts like a Firewire hard drive which can be connected to
    > another computer.


    That feature is quite old on Macs. I think it might date back to some of the
    earliest PowerBook models from 1992. Only in those days there was no
    FireWire, but Macs had SCSI ports then. So it was called "SCSI disk mode",
    or maybe "SCSI target mode". But it was still the "T" key you held down.

    But really, why is this feature necessary? It only seems needed if the OS
    doesn't let you access certain files via a network while it's running. That
    was true of old MacOS, I'm surprised it's still true of OS X today.

    > Great for copying lots of files, or to repair the
    > internal hard drive, or to boot one computer from another's internal
    > drive, or to migrate the entire system over to a new computer (which Mac
    > OS X offers to do during the initial setup of a new computer).


    All of which you can do on a Linux system while it's still running.

    >> It seems so much simpler on a Linux system. :)

    >
    > I expect most Linux systems would normally start up in the equivalent of
    > Mac OS X's verbose mode. (My IPCop installation spits out pages of
    > status messages on the console while starting up.)


    Some distros, yes. Others put up a pretty graphical display, but there's
    usually small print at the bottom saying "Press Esc for details" or
    something like that.

    > The Mac's policy has always been to have the normal startup sequence a
    > clean and largely icon or picture-based experience, avoiding excessive
    > use of text and technical terms, except if something goes wrong.


    The normal Linux policy is to first present the bootloader menu. That has a
    default option that will be selected if you don't hit a key within the
    timeout interval (e.g. 8 seconds). For instance, selecting single-user mode
    is as simple as typing the word "single", which gets appended to the kernel
    command line. I think that's better than remembering cryptic keystrokes,
    don't you think so?
     
    Lawrence D'Oliveiro, Aug 15, 2007
    #9
  10. Lawrence D'Oliveiro

    David Empson Guest

    Lawrence D'Oliveiro <_zealand> wrote:

    > In message <1i2v3i5.bicjda7f15b1N%>, David Empson
    > wrote:
    >
    > > My favourite is the 'T' key, which puts a Mac into Firewire target mode.
    > > It then acts like a Firewire hard drive which can be connected to
    > > another computer.

    >
    > That feature is quite old on Macs. I think it might date back to some of the
    > earliest PowerBook models from 1992. Only in those days there was no
    > FireWire, but Macs had SCSI ports then. So it was called "SCSI disk mode",
    > or maybe "SCSI target mode". But it was still the "T" key you held down.


    Old PowerBook models get into SCSI target mode by using a special SCSI
    adapter. The ones I've seen have a switch on them which selects between
    normal operation and target mode.

    The 'T' key was introduced with Firewire Target Mode (early 2000).

    > But really, why is this feature necessary? It only seems needed if the OS
    > doesn't let you access certain files via a network while it's running. That
    > was true of old MacOS, I'm surprised it's still true of OS X today.


    Mac OS X follows a standard Unix privileges model. If you log into a
    computer via the network, your access to files is determined by
    ownership and access privileges, according to who you log in as.

    The standard file sharing protocol (AFP) doesn't provide any way to
    bypass the privilege system.

    You can get unrestricted access if you are able to ssh into the Mac as
    an administrative user then use sudo to get root privileges. You can
    only do this if the computer has been set up to allow remote login
    (disabled by default).

    The average Mac user doesn't want to go fiddling around with command
    line tools, so doing an "unrestricted file copy" via a network is beyond
    the capabilities of most Mac users.

    There might be software which makes this task easier, but Firewire
    target mode is signficantly easier and makes more sense to the average
    user.

    Setting up network file transfers requires enabling sharing on at least
    one computer, making sure your TCP/IP settings are compatible, and
    knowing at least one user account and password on the computer.

    Firewire target mode requires no special knowledge other than how to use
    an external hard drive, where to plug in the Firewire cable, and when to
    press the 'T' key.

    > > Great for copying lots of files, or to repair the
    > > internal hard drive, or to boot one computer from another's internal
    > > drive, or to migrate the entire system over to a new computer (which Mac
    > > OS X offers to do during the initial setup of a new computer).

    >
    > All of which you can do on a Linux system while it's still running.


    Yes, if you know how or have the right tools. The same applies to Mac OS
    X, but most Mac users don't have the technical skills of the average
    Linux expert.

    > > The Mac's policy has always been to have the normal startup sequence a
    > > clean and largely icon or picture-based experience, avoiding excessive
    > > use of text and technical terms, except if something goes wrong.

    >
    > The normal Linux policy is to first present the bootloader menu. That has a
    > default option that will be selected if you don't hit a key within the
    > timeout interval (e.g. 8 seconds). For instance, selecting single-user mode
    > is as simple as typing the word "single", which gets appended to the kernel
    > command line. I think that's better than remembering cryptic keystrokes,
    > don't you think so?


    Ignoring the issue of people wanting to use multiple operating systems
    for a moment:

    The average Mac user with a current Mac model has a single hard drive
    with a single partition, and a single installation of Mac OS X on it.
    The only thing they do at startup is boot the same operating system.
    (They might have additional drives for backups or extra data storage,
    but only a few would ever boot from them.)

    They might boot from CD once in a blue moon, so if they know about the
    'C' key it will save them a little time. (There is a GUI tool to select
    the startup volume if they don't know the shortcut.)

    Why present options to a non-technical person who will never use them,
    and why waste time waiting for an answer to a question which will always
    be the same?

    Things are slightly more complex if you want to install more than one
    operating system. You might need to know about things like partitioning
    the hard drive. Someone with an older Mac might have both Mac OS 9 and
    Mac OS X on it. Linux is an option on most Macs, and booting directly
    into Windows is an option on current models (via Boot Camp).

    Changing the startup volume is normally done with a GUI tool (on Mac OS
    X and Mac OS 9; probably a command line tool on Linux and a special
    application on Windows). Knowing about the Option key will let you pick
    a volume (and its corresponding OS) when you start up.

    That's two startup keys which might be useful to slightly more advanced
    Mac users.

    The other special startup keys are used so rarely that the average Mac
    user doesn't need to know about them. If they do, they are documented in
    the online help and in the troubleshooting section of the manual.

    They are more commonly used when diagnosing or solving problems, and
    that's when someone with more experience (who knows about these details)
    gets called in. Problems that require anything more complex than booting
    from CD are extremely rare. For example, I've been doing Mac OS X tech
    support for about six years on dozens of computers, and I can only think
    of two occasions where I needed single user mode, though I've sometimes
    used it just because it was the quickest way to solve a problem.

    --
    David Empson
     
    David Empson, Aug 15, 2007
    #10
  11. Lawrence D'Oliveiro

    whoisthis Guest

    And another really useful ability of target mode is where you transfer
    users from one machine to another using Migration Assistant.

    AND

    Being able to to data recovery without needing to remove the HD from the
    machine.... particularly useful for laptops. I have been able to recover
    an accidentally deleted PhD thesis and a whole pile of other things this
    way.

    My workmates who do linux/windows have often stated that they wish they
    had "target mode" of their machines they look after, it just saves so
    much time and does not void warranties by having to crack open the
    machine to get the HD out.
     
    whoisthis, Aug 15, 2007
    #11
  12. In message <1i2wz9g.19ofvzzawqm99N%>, David Empson
    wrote:

    > Lawrence D'Oliveiro <_zealand> wrote:
    >
    >> In message <1i2v3i5.bicjda7f15b1N%>, David Empson
    >> wrote:
    >>
    >> > My favourite is the 'T' key, which puts a Mac into Firewire target
    >> > mode. It then acts like a Firewire hard drive which can be connected to
    >> > another computer.

    >>
    >> That feature is quite old on Macs. I think it might date back to some of
    >> the earliest PowerBook models from 1992. Only in those days there was no
    >> FireWire, but Macs had SCSI ports then. So it was called "SCSI disk
    >> mode", or maybe "SCSI target mode". But it was still the "T" key you held
    >> down.

    >
    > Old PowerBook models get into SCSI target mode by using a special SCSI
    > adapter. The ones I've seen have a switch on them which selects between
    > normal operation and target mode.
    >
    > The 'T' key was introduced with Firewire Target Mode (early 2000).


    OK, excuse my faulty memory. :)

    >> But really, why is this feature necessary? It only seems needed if the OS
    >> doesn't let you access certain files via a network while it's running.
    >> That was true of old MacOS, I'm surprised it's still true of OS X today.

    >
    > Mac OS X follows a standard Unix privileges model. If you log into a
    > computer via the network, your access to files is determined by
    > ownership and access privileges, according to who you log in as.
    >
    > The standard file sharing protocol (AFP) doesn't provide any way to
    > bypass the privilege system.


    But we're not talking about bypassing the privilege system. Simply that some
    OSes lock certain files while they're in use, so you can't access them
    while the OS is running. The old MacOS used to do this (for network
    access), also Windows does this. But Linux doesn't.

    > The average Mac user doesn't want to go fiddling around with command
    > line tools, so doing an "unrestricted file copy" via a network is beyond
    > the capabilities of most Mac users.


    You don't need to use a command line to access files via SSH. KDE includes a
    standard "fish://" protocol handler that gives you full GUI access to
    manipulating files, drag and drop between local and remote machines, etc. I
    believe Gnome also has something similar.

    > Setting up network file transfers requires enabling sharing on at least
    > one computer, making sure your TCP/IP settings are compatible, and
    > knowing at least one user account and password on the computer.


    Strange, I thought Apple was one of the prime movers behind the Zeroconf
    effort (a.k.a. Rendezvous/Bonjour) to take much of the pain out of this.

    >> > Great for copying lots of files, or to repair the
    >> > internal hard drive, or to boot one computer from another's internal
    >> > drive, or to migrate the entire system over to a new computer (which
    >> > Mac OS X offers to do during the initial setup of a new computer).

    >>
    >> All of which you can do on a Linux system while it's still running.

    >
    > Yes, if you know how or have the right tools.


    Nope, just the same ones you would use normally. Nothing special at all.

    >> > The Mac's policy has always been to have the normal startup sequence a
    >> > clean and largely icon or picture-based experience, avoiding excessive
    >> > use of text and technical terms, except if something goes wrong.

    >>
    >> The normal Linux policy is to first present the bootloader menu. That has
    >> a default option that will be selected if you don't hit a key within the
    >> timeout interval (e.g. 8 seconds). For instance, selecting single-user
    >> mode is as simple as typing the word "single", which gets appended to the
    >> kernel command line. I think that's better than remembering cryptic
    >> keystrokes, don't you think so?

    >
    > Ignoring the issue of people wanting to use multiple operating systems
    > for a moment:
    >
    > The average Mac user with a current Mac model has a single hard drive
    > with a single partition, and a single installation of Mac OS X on it.
    > The only thing they do at startup is boot the same operating system.


    Well, that's the thing. Now that Macs have Intel processors, increasing
    numbers of their users also want to run other operating systems as
    well--witness all the interest in Boot Camp, Parallels and so on. So the
    issue of handling multiple operating systems is becoming more important.

    > They might boot from CD once in a blue moon, so if they know about the
    > 'C' key it will save them a little time. (There is a GUI tool to select
    > the startup volume if they don't know the shortcut.)


    Again, why is that kind of thing necessary? In the BIOS on my Shuttles I
    have the boot order permanently set to give priority to the CD over the
    hard drive. If there's a CD in the drive at boot time, it starts off that.
    Otherwise it starts off the hard drive. Simple--no special keys to press.
     
    Lawrence D'Oliveiro, Aug 16, 2007
    #12
  13. In message <>, whoisthis wrote:

    > My workmates who do linux/windows have often stated that they wish they
    > had "target mode" of their machines they look after...


    Tell them (Windows techies included) to use a Linux CD as a rescue disc to
    boot up the machine with. Most Linux install CDs will offer you a basic
    functional Linux shell environment; or use a live CD to get a
    full-functioning GUI. Then you have access to a full range of system
    checking and recovery tools to fix up the hard drive.
     
    Lawrence D'Oliveiro, Aug 16, 2007
    #13
  14. Lawrence D'Oliveiro

    whoisthis Guest

    In article <fa0jfv$mli$>,
    Lawrence D'Oliveiro <_zealand> wrote:

    > In message <>, whoisthis wrote:
    >
    > > My workmates who do linux/windows have often stated that they wish they
    > > had "target mode" of their machines they look after...

    >
    > Tell them (Windows techies included) to use a Linux CD as a rescue disc to
    > boot up the machine with. Most Linux install CDs will offer you a basic
    > functional Linux shell environment; or use a live CD to get a
    > full-functioning GUI. Then you have access to a full range of system
    > checking and recovery tools to fix up the hard drive.


    unless it is ntfs formatted. I have yet to see a lice CD do that, but
    equally well if you are recovering files then you need another drive to
    write to, and no a network mounted device is not an option for
    recovering 30-40 gigs of data.
     
    whoisthis, Aug 16, 2007
    #14
  15. In message <>, whoisthis wrote:

    > In article <fa0jfv$mli$>,
    > Lawrence D'Oliveiro <_zealand> wrote:
    >
    >> In message <>, whoisthis
    >> wrote:
    >>
    >> > My workmates who do linux/windows have often stated that they wish they
    >> > had "target mode" of their machines they look after...

    >>
    >> Tell them (Windows techies included) to use a Linux CD as a rescue disc
    >> to boot up the machine with. Most Linux install CDs will offer you a
    >> basic functional Linux shell environment; or use a live CD to get a
    >> full-functioning GUI. Then you have access to a full range of system
    >> checking and recovery tools to fix up the hard drive.

    >
    > unless it is ntfs formatted. I have yet to see a li[v]e CD do that...


    Knoppix 5.1.1 apparently has NTFS-3G in it, and I also found mention of
    Scientific Linux 5 and the Helix Forensic Live CD. All with just a couple
    of minutes of Googling.

    > ... but equally well if you are recovering files then you need another
    > drive to write to, and no a network mounted device is not an option for
    > recovering 30-40 gigs of data.


    I've just been mirroring about 380GB of data from one of a client's older
    servers onto the newest one, using rsync. Total time taken, about 20 hours.
    So 30-40 gigs should be quite manageable over a network--even better if you
    can get a gigabit connection between the machines.
     
    Lawrence D'Oliveiro, Aug 16, 2007
    #15
  16. Lawrence D'Oliveiro

    whoisthis Guest

    In article <fa0tvk$ag5$>,
    Lawrence D'Oliveiro <_zealand> wrote:

    > I've just been mirroring about 380GB of data from one of a client's older
    > servers onto the newest one, using rsync. Total time taken, about 20 hours.
    > So 30-40 gigs should be quite manageable over a network--even better if you
    > can get a gigabit connection between the machines.


    well the nice thing is that as far as the system is concerned the
    machine is simply another drive and therefore all system utilities work
    on it. Until you get to use target mode in anger you will never really
    appreciate how fantastic an idea it is.
     
    whoisthis, Aug 16, 2007
    #16
  17. In message <>, whoisthis wrote:

    > In article <fa0tvk$ag5$>,
    > Lawrence D'Oliveiro <_zealand> wrote:
    >
    >> I've just been mirroring about 380GB of data from one of a client's older
    >> servers onto the newest one, using rsync. Total time taken, about 20
    >> hours. So 30-40 gigs should be quite manageable over a network--even
    >> better if you can get a gigabit connection between the machines.

    >
    > well the nice thing is that as far as the system is concerned the
    > machine is simply another drive and therefore all system utilities work
    > on it.


    But on Linux machines, all system utilities work on the drive anyway.

    > Until you get to use target mode in anger you will never really
    > appreciate how fantastic an idea it is.


    So why is it only Mac laptops that have it, then?
     
    Lawrence D'Oliveiro, Aug 16, 2007
    #17
  18. Lawrence D'Oliveiro

    whoisthis Guest

    In article <fa10po$emq$>,
    Lawrence D'Oliveiro <_zealand> wrote:


    > > Until you get to use target mode in anger you will never really
    > > appreciate how fantastic an idea it is.

    >
    > So why is it only Mac laptops that have it, then?


    Incorrect, almost all Macs have had it since they had firewire built
    onto the motherboard. It works on my G5 tower, my eMac, my iBook, My
    MacbookPro, my iMac G3/400, G4/400. When in target mode you can even use
    them as a boot drive for another machine. I am even able to then use the
    built in DVD of the target mode machine so I can install software from
    its DVD drive onto a machine which may only have a CD drive in it.

    Hell, I have even used target mode so that I had one machine as a master
    disk (dual boot OSX/Windows) then used 3 instances of dd to clone the
    whole drive including boot partitions etc onto 3 other machines at the
    one time. No need for a network switch, just some firewire cables.
     
    whoisthis, Aug 16, 2007
    #18
  19. Lawrence D'Oliveiro

    David Empson Guest

    Lawrence D'Oliveiro <_zealand> wrote:

    > But we're not talking about bypassing the privilege system. Simply that some
    > OSes lock certain files while they're in use, so you can't access them
    > while the OS is running. The old MacOS used to do this (for network
    > access), also Windows does this. But Linux doesn't.


    Nor does Mac OS X (as far as I know). If you have read access to a file
    then you can copy it. There isn't any distinction between local and
    network access.

    > In message <1i2wz9g.19ofvzzawqm99N%>, David Empson
    > wrote:
    >
    > > The average Mac user doesn't want to go fiddling around with command
    > > line tools, so doing an "unrestricted file copy" via a network is beyond
    > > the capabilities of most Mac users.

    >
    > You don't need to use a command line to access files via SSH. KDE includes a
    > standard "fish://" protocol handler that gives you full GUI access to
    > manipulating files, drag and drop between local and remote machines, etc. I
    > believe Gnome also has something similar.


    I haven't gone looking for anything sufficiently Mac-aware (it would
    have to deal with extended file system metadata and resource forks for
    maximum compatibility, though Mac OS X is gradually moving away from
    those aspects of the Mac).

    > > Setting up network file transfers requires enabling sharing on at least
    > > one computer, making sure your TCP/IP settings are compatible, and
    > > knowing at least one user account and password on the computer.

    >
    > Strange, I thought Apple was one of the prime movers behind the Zeroconf
    > effort (a.k.a. Rendezvous/Bonjour) to take much of the pain out of this.


    Yes, that's fine for the TCP/IP layer, as long as the user hasn't set up
    a custom TCP/IP configuration. They still need to know about enabling
    file sharing, and how to connect to another computer, and deal with
    logging on with the right user name and password.

    > >> > Great for copying lots of files, or to repair the
    > >> > internal hard drive, or to boot one computer from another's internal
    > >> > drive, or to migrate the entire system over to a new computer (which
    > >> > Mac OS X offers to do during the initial setup of a new computer).
    > >>
    > >> All of which you can do on a Linux system while it's still running.

    > >
    > > Yes, if you know how or have the right tools.

    >
    > Nope, just the same ones you would use normally. Nothing special at all.


    I'm intrigued. I'd like to know (in broad terms) how you do would do
    each of the following tasks, given two Linux computers with an Ethernet
    connection. These are all easy to do between two Macs using Firewire
    target mode (and a direct Firewire cable connection).

    In each case, computer B is the one in target mode, and it is expected
    that it will be restarted afterwards.

    1. Get computer A to boot directly from the hard drive of computer B,
    over the network, while computer B sits dormant and doesn't interfere.
    Once up and running, computer A can do anything to its own drive
    (including formatting it), and any file-level operation on computer B's
    drive that it could achieve if that drive was physically installed in
    computer A.

    2. Boot computer A normally (from its own drive) and give it block level
    access to the drive of computer B over the network, e.g. so it can run
    fsck, or format or partition the drive on computer B.

    3. Boot computer A normally (from its own drive) and copy user accounts
    and installed applications (including support files) from computer B to
    computer A, with automatic modifications to avoid issues like
    conflicting account names or user IDs.

    4. Same as 3, but do it during initial installation of Linux on computer
    A, without having to do anything more than following on-screen prompts
    and data entry on computer A, and a single keypress to get computer B
    into the right state.

    > > The average Mac user with a current Mac model has a single hard drive
    > > with a single partition, and a single installation of Mac OS X on it.
    > > The only thing they do at startup is boot the same operating system.

    >
    > Well, that's the thing. Now that Macs have Intel processors, increasing
    > numbers of their users also want to run other operating systems as
    > well--witness all the interest in Boot Camp, Parallels and so on. So the
    > issue of handling multiple operating systems is becoming more important.


    I agree. I was going to add that as footnote but didn't remember until
    too late.

    I think it would be a good idea if Apple adds an optional feature on
    Intel Macs which allows the startup disk selector to be entered
    automatically, and to boot the default system if no choice is made
    within a few seconds.

    This would have to be something that an advanced user enabled explicitly
    - it would not be on by default.

    > > They might boot from CD once in a blue moon, so if they know about the
    > > 'C' key it will save them a little time. (There is a GUI tool to select
    > > the startup volume if they don't know the shortcut.)

    >
    > Again, why is that kind of thing necessary? In the BIOS on my Shuttles I
    > have the boot order permanently set to give priority to the CD over the
    > hard drive. If there's a CD in the drive at boot time, it starts off that.
    > Otherwise it starts off the hard drive. Simple--no special keys to press.


    Not sure about that one. When Macs had floppy drives and no CD drives
    (back in the 68K era), they booted from floppy if it contained a valid
    system, otherwise they started up from the hard drive.

    Macs have never automatically booted from CD (except if the configured
    startup volume doesn't have a valid system or is otherwise inaccessible,
    and there is a bootable CD in the drive).

    It might be regarded as a safety measure - if the user accidentally
    leaves a bootable CD in the drive at startup time, it is ignored unless
    they also hold down the right key.

    It also saves time not having to read the CD at startup just to check
    whether there is a bootable system on it.

    It could be related to the Mac's insistence on locking out the manual CD
    eject button while the disc is mounted (or not having an eject button at
    all). If the CD was the default boot device, then after booting from a
    CD you would have difficulty getting back to booting off the hard drive,
    as the CD is still in the drive until you can get to a point where you
    can push the manual eject button (if there is one) or the software eject
    key.

    I've never been entirely happy about this aspect of CD handling on a
    Mac.

    --
    David Empson
     
    David Empson, Aug 16, 2007
    #19
  20. In message <1i2ytpg.1k079avekrhd7N%>, David Empson
    wrote:

    > Lawrence D'Oliveiro <_zealand> wrote:
    >
    >> In message <1i2wz9g.19ofvzzawqm99N%>, David Empson
    >> wrote:
    >>
    >> >> > Great for copying lots of files, or to repair the
    >> >> > internal hard drive, or to boot one computer from another's internal
    >> >> > drive, or to migrate the entire system over to a new computer (which
    >> >> > Mac OS X offers to do during the initial setup of a new computer).
    >> >>
    >> >> All of which you can do on a Linux system while it's still running.
    >> >
    >> > Yes, if you know how or have the right tools.

    >>
    >> Nope, just the same ones you would use normally. Nothing special at all.

    >
    > I'm intrigued. I'd like to know (in broad terms) how you do would do
    > each of the following tasks, given two Linux computers with an Ethernet
    > connection. These are all easy to do between two Macs using Firewire
    > target mode (and a direct Firewire cable connection).
    >
    > In each case, computer B is the one in target mode, and it is expected
    > that it will be restarted afterwards.
    >
    > 1. Get computer A to boot directly from the hard drive of computer B,
    > over the network, while computer B sits dormant and doesn't interfere.
    > Once up and running, computer A can do anything to its own drive
    > (including formatting it), and any file-level operation on computer B's
    > drive that it could achieve if that drive was physically installed in
    > computer A.


    This is just standard network booting capability. Thin clients, for
    instance, use this all the time. See PXELINUX <http://syslinux.zytor.com/>.

    > 2. Boot computer A normally (from its own drive) and give it block level
    > access to the drive of computer B over the network, e.g. so it can run
    > fsck, or format or partition the drive on computer B.


    NBD <http://nbd.sourceforge.net/> is a standard feature of current Linux
    kernels.

    > 3. Boot computer A normally (from its own drive) and copy user accounts
    > and installed applications (including support files) from computer B to
    > computer A, with automatic modifications to avoid issues like
    > conflicting account names or user IDs.


    rsync <http://samba.anu.edu.au/rsync/> is a standard tool on every
    self-respecting Linux distro. It will correctly copy files with
    username "fred" on machine A to username "fred" on machine B, even if their
    user IDs are different.

    > 4. Same as 3, but do it during initial installation of Linux on computer
    > A, without having to do anything more than following on-screen prompts
    > and data entry on computer A, and a single keypress to get computer B
    > into the right state.


    You mean, like FAI <http://www.informatik.uni-koeln.de/fai/>?

    > It could be related to the Mac's insistence on locking out the manual CD
    > eject button while the disc is mounted (or not having an eject button at
    > all).


    Actually, they all lock the eject button nowadays, it isn't just Macs.

    I always thought the old prevent-floppy-ejection-while-mounted feature was a
    wonderful idea, given the frequency with which users of other platforms
    would corrupt their floppies by ejecting them at the wrong time.
     
    Lawrence D'Oliveiro, Aug 17, 2007
    #20
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