adamd@rhi.hi.is (Adam David) (01/15/91)
I just found a strange feature in TOS, by it's very presence in 1.2 there is a strong possibility that it hasn't been fixed in TT TOS either. If Drive A: is broken or disconnected and drive B: fully functional TOS gets rather confused about where the disk drives are. Say we boot the ST with only B: drive connected. (possible reasons: to get a quick boot off hard disk without waiting for drive A: to timeout, or to get almost instant "clean" boot on a system without hard disk, or to boot off a network without floppy boot overheads / disadvantages and yet retaining access to a local floppy drive). What actually happens is this: TOS notices that drive A: is missing and drive B: is present. Seeing only one drive the TOS figures that it must be drive A: and installs logical drives A: and B: to physical drive A: which does not exist. TOS still tries for 30 seconds to read drive A: and finally concludes that drive A: does not have a disk in it. ( To agony aunt: Why is that timeout so long? If the disk isn't in the drive, what's the point in trying to read it? ) For comparison, if TOS finds no drives it is sensible enough not to try reading a missing drive until timeout. Of course this faulty logic dates back to the early days of TOS and its predecessors, when RAM-loadable OS was in fashion (not that there's anything fundamentally wrong with RAM-based OS, mind you). The most acceptable way of fixing this is (IMHO) to make a much better attempt at deciding whether a disk is in the drive being accessed (thus reducing timeout to absolute minimum, the main function of timeout being error recovery for a disk which is present but damaged), and to install both floppies onto physical drive B: if that is the setup. This bug is probably seldom encountered, but is an unfortunate oversight. If fixed that would allow TOS to boot from logical drive A: whether installed on physical drive A: or B:. This would mean that if the internal drive fails for whatever reason, one could still continue to use a two-drive ST (without any modifications or repairs) as a one-drive ST (the same might apply to TT ? ). Actually some of the older Atari drives are rather prone to failure, some customer downtime would have been eliminated if the drive assignment had been in order (it's easier to work on a one-drive computer than a no-drive one). Not everyone dares open the box and change wires / links to get things fixed themselves outside of normal business hours. Does anyone know whether TT TOS suffers from this fault? -- Adam David. adamd@rhi.hi.is