[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Disk II Family's Phase
Bryan Parkoff <BParkoff@satx.rr.com> wrote in message
gf6cnUFJ3aW3uc2jXTWQkQ@giganews.com">news:gf6cnUFJ3aW3uc2jXTWQkQ@giganews.com...
> It seems to be interesting that standard Disk Drive only uses Phase0
> that is turned on for reading and writing, but all Phase0, Phase1, Phase2,
> and Phase3 are always turned off. I wonder why Phase1, Phase2, and Phase
3
> are not used for turning on.
> Please explain what Phase do. I understand that it is used for
stepping
> arm to move from outer toward inner.
>
> Is it true that stepping arm always move from outer toward inner by
> reading SELECTIVE track and sector? Does it mean that software has NO WAY
> TO TELL hardware to LOCATE track and sector. The hardware's job is to
> retrieve each bit by reading from outer toward inner. In fact is that it
is
> the software's job to SEARCH track and sector before track and sector are
> compared to match user's desire track and sector BEFORE 256 bytes in a
> sector dump into memory.
> Does it make sense?
>
> --
> Yours Truly,
>
> Bryan Parkoff
> BParkoff@satx.rr.com
>
>
If I remember what I read recently, Phase # is described as a clock.
Phase 0 = 12, 1 = 3, 2 = 6, 3 = 9. Being that the read write head is
so large on the 5.25 drives, the tracks are only set on 12 and 6.
You would first search for track 0 indicator and drive runs counter-
clockwise until it is reached, then from there being it is on 12 0'clock,
you would then for track one turn off phase 0 and turn on phase 1,
turn off 1, then turn on 2, then off 2. now you are on track 1 and so on.
Also, as far as I am aware of, the read/write timing is of utmost importance
since the speed of the disk spinning is critically set to I believe 300 RPM.
If your timing is not exact in program, you will not read/write the proper
byte.
If I am not exactly correct, please feel free anyone to correct me as I do
hate
to give out incorrect info. I hope this answered your question somewhat.
Yes it would make perfect sense to be able to search track/sector but from
what I've read that isn't how it works.
Bill @ GarberStreet Enterprises
http://garberstreet.netfirms.com
---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.449 / Virus Database: 251 - Release Date: 1/27/03