[mythtv-users] 2 TB Hard Drive Recommendations

[jrlowry376 at comcast.net]

> Hi
>
> On 6 December 2010 21:41, Andre <mythtv-list at dinkum.org.uk> wrote:
>> I'm sure it's possible to have one track that's low density and readable
>> without all the clever trickery usually used, then a minimal firmware
>> bootstrap loader that knows only this track could load up the full
>> firmware. Sounds like a common practice, should be ok provided the
>> bootstrap loader knows how to re-write the firmware track!
>
> I'm not sure if you've ever designed embedded firmware before (btw,
> that's what I do for a living), but the amount of smarts required to
> start spinning the disk, move the head to the right spot, read the
> data, load the firmware in RAM and start is quite massive to start
> with.
>
> As you said, you would need a firmware for just that (probably on
> flash). Constraints on flash make them all of a minimum size to start
> with.
>
> The drive needs a writing location to record the bad sectors and other
> bad spot detected on the disk too..

In the '80s I worked on Data General Argus disk drives, there where three
versions with capacities of 354, 592 and 862 Megabytes. I can't remember
if they where 6809 or Data General micro Nova based boxes.

I do remember that the firmware was stored on the drive, and was easily
upgraded by running diagnostics on the attached super mini computer.
There where 16 spare sectors per cylinder, remapping was also a diagnostic
activity. If you ran out of spare sectors in a cylinder you replaced the
HDA.

We've come a long way from those drives (in a lot of ways) these drives
where 19" wide, 10.5" tall and 20+" deep and required two engineers to
replace a complete drive. Three of the 354s where sold as package in a
meter high rack as a Giga-stack.

I'll agree that it may take a lot of code to run internal diagnostics,
spin a drive and read in firmware, but it's a subset of the code required
to run the drive in normal operation.

I'm not a bean counter, but I'm sure there was a lot of thought put into
the decision to store the firmware on the drive.

With all of this talk about drive reliability it's useful to read the
Google drive reliability report.

Jack