Timeline for On DOS computers, what would the PARK command do?
Current License: CC BY-SA 4.0
6 events
| when toggle format | what | by | license | comment | |
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| Dec 9, 2024 at 16:12 | comment | added | supercat | ...a secondary motor (which could be a dime-store brush motor) to cock the spring. | |
| Dec 9, 2024 at 16:11 | comment | added | supercat | @manassehkatz-Moving2Codidact: Thinking a bit more, a stepper motor could have supported auto-retract if the heads could move with minimal friction, and the drive included a spring that would retract the heads when the head motor was unpowered. This would have required that the stepper motor be strong enough to overcome the combined spring and friction forces, and kept the motor powered any time the heads were supposed to be in a non-parked position; this would have more than doubled the torque requirement for the motor, but that limitation could have been overcome by adding... | |
| Dec 9, 2024 at 5:56 | comment | added | ssokolow | @manassehkatz-Moving2Codidact I remember reading that, at least in its first draft, IDE was just designed as a way to extend the IDE bus out over a ribbon cable and move the option ROM from the controller (now secured to the drive) to the motherboard to reduce the opportunity for incompatibilities. (Which would explain why bad drive electronics may prevent the system from POSTing... though not why it can still happen with SATA.) | |
| Jan 20, 2022 at 18:06 | comment | added | supercat | @manassehkatz-Moving2Codidact: If an IDE drive used a stepper motor, making it auto-retract heads on shutdown would require that the drive store enough energy to accomplish that. Nothing about the IDE standard would forbid a drive from including and using such energy storage and circuitry to use it, but the electronics to accomplish that would almost certainly be more expensive than the electronics to use a voice coil mechanism, thus effectively eliminating almost any possible advantage a stepper motor would have. | |
| Jan 20, 2022 at 17:32 | comment | added | manassehkatz-Moving 2 Codidact | As far as IDE, my understanding (but I haven't researched it) is that IDE included a lot more circuitry on the drive (i.e., most of the "controller" that previously was a separate card), and that parking could therefore be incorporated, in whatever fashion deemed best by the manufacturer based on the particular drive technology, taking that task away from the user and/or operating system. | |
| Jan 20, 2022 at 16:24 | history | answered | supercat | CC BY-SA 4.0 |