4 ms·

Lots of tape drives from that era could do that. You've got big heavy motors and spindles, which means lots of inertia. Tell a drive to spin up to full speed, t

Lots of tape drives from that era could do that. You've got big heavy motors and spindles, which means lots of inertia. Tell a drive to spin up to full speed, then abruptly stop, and you got lots of angular momentum that still needs to be dissipated. As the spindle assembly is anchored to the chassis, this ends up getting dissipated through the chassis as a quick movement. Spool up the spindles in the opposite directiion and then abruptly stop, and you've just made it step forward. Repeat many times and you've got a walking disk drive.

minipci1321 10y ago
> and then abruptly stop These were first computers I was exposed to. As students and later young engineers working with them, we were taught an important principle: "nothing you can do in software can break the hardware". Imagine then my bewilderment when, working with a tape and having some strange-looking "Attention required", I went down to the ceiling only to see the tape still on reels but cut in two pieces.
- dzdt 10y ago
  Its funny. In the early days of consumer PC's the feeling was very much the opposite. There were persistent rumors of "killer poke" commands (some of which were at least partially true) where an incorrect software command could destroy the hardware.
  - minipci1321 10y ago
    I am not sure whether that principle they taught us was holding 100% of the time, but it for sure helped -- we were fearless ;-). I must say I am glad that I started my developer career by doing systems programming in IBM OSes. It felt like officiating in a temple at the time and age. Compared to channel programming and starting I/O asynchronously, twiddling bits in some register on a PC in a loop on main (and only) CPU felt just wrong to me ;-). Who knew...
  - bitwize 10y ago
    Commodore computers were particularly susceptible to these. There was a famous one for the PET which could blow out the CRT. I'm also pretty sure I accidentally killed at least one VIC-20 with another, more different poke...
    - deleted 10y ago
      [deleted]
    - colejohnson66 10y ago
      For an explanation on why that would kill your CRT: http://www.6502.org/users/andre/petindex/poke/index.html http://www.6502.org/users/andre/petindex/poke/index.html

minipci1321 10y ago

> and then abruptly stop These were first computers I was exposed to. As students and later young engineers working with them, we were taught an important principle: "nothing you can do in software can break the hardware". Imagine then my bewilderment when, working with a tape and having some strange-looking "Attention required", I went down to the ceiling only to see the tape still on reels but cut in two pieces.

dzdt 10y ago
Its funny. In the early days of consumer PC's the feeling was very much the opposite. There were persistent rumors of "killer poke" commands (some of which were at least partially true) where an incorrect software command could destroy the hardware.
- minipci1321 10y ago
  I am not sure whether that principle they taught us was holding 100% of the time, but it for sure helped -- we were fearless ;-). I must say I am glad that I started my developer career by doing systems programming in IBM OSes. It felt like officiating in a temple at the time and age. Compared to channel programming and starting I/O asynchronously, twiddling bits in some register on a PC in a loop on main (and only) CPU felt just wrong to me ;-). Who knew...
- bitwize 10y ago
  Commodore computers were particularly susceptible to these. There was a famous one for the PET which could blow out the CRT. I'm also pretty sure I accidentally killed at least one VIC-20 with another, more different poke...
  - deleted 10y ago
    [deleted]
  - colejohnson66 10y ago
    For an explanation on why that would kill your CRT: http://www.6502.org/users/andre/petindex/poke/index.html http://www.6502.org/users/andre/petindex/poke/index.html