30 Oct
2001
30 Oct
'01
6:19 a.m.
On Oct 30, 10:32, Fred Cisin (XenoSoft) wrote:
3.5" 1.4M (I have NEVER seen a 1.44M format!) are
also at 300RPM
However, many original 3.5" (SSDD not HD) ran at 600rpm, but with 2x the
normal data rate (so the disks could also be used in 300rpm drives at
normal data rates).
--
Pete Peter Turnbull
Network Manager
University of York
30 Oct
30 Oct
8:17 a.m.
I recall the Amiga having a high-density external disk addon that ran at
1/2 speed so Commodore wouldn't have to include a faster fdd controller
chip. The bad news. The good news is that it worked on all Amiga
machines right out of the box.
The ATR8000 and ATR8500 CP/M boxes DO for Certain use the index hole to
time the drive's rotation to determine if it is an 8" or a 5.25" mech
running. I've used a couple of 3.5" high-density drives on them and
gotten up to 1.35mb in CP/M and 1mb in Spartados. The trick is getting a
3.5" mech that has a big ol' block of jumpers on it. You can fiddle with
the jumpers and make the drive emulate a 77track 8" mech.
As for the index hole, this wasn't such a bad thing unless you wanted to
use 'flippy' disks in an ATR. Atari drives don't use the hole at all so
flipping the disk works fine. With the ATR as a controller though you
have to punch another index hole in the disk or use a standard mech with
dual sets of index hole sensor such as those 'flippy' drives made by
Pertec and Aerocomp -never seen em', I just know they made them.
And then there are these freaky 3" disks I have for an Amstrad I once
owned.....
Regards,
Jeff
In <10110302019.ZM26540(a)mindy.dunnington.u-net.com>om>, on 10/30/01
at 08:19 PM, pete(a)dunnington.u-net.com (Pete Turnbull) said:
On Oct 30, 10:32, Fred Cisin (XenoSoft) wrote:
> 3.5" 1.4M (I have NEVER seen a 1.44M format!)
are also at 300RPM
However, many original 3.5" (SSDD not HD) ran at
600rpm, but with 2x the
normal data rate (so the disks could also be used in 300rpm drives at
normal data rates).
--
-----------------------------------------------------------
Jeffrey S. Worley
Asheville, NC USA
828-6984887
UberTechnoid(a)Home.com
-----------------------------------------------------------
8:53 a.m.
On Tue, 30 Oct 2001 UberTechnoid(a)home.com wrote:
I recall the Amiga having a high-density external disk
addon that ran at
1/2 speed so Commodore wouldn't have to include a faster fdd controller
chip. The bad news. The good news is that it worked on all Amiga
machines right out of the box.
How was reliability for it? The Weltec half speed 1.2M 5.25" did NOT work
well.
The ATR8000 and ATR8500 CP/M boxes DO for Certain use
the index hole to
time the drive's rotation to determine if it is an 8" or a 5.25" mech
running. I've used a couple of 3.5" high-density drives on them and
gotten up to 1.35mb in CP/M and 1mb in Spartados. The trick is getting a
3.5" mech that has a big ol' block of jumpers on it. You can fiddle with
the jumpers and make the drive emulate a 77track 8" mech.
The REAL easy (just a weird cable) is to put a 5.25" 1.2M in place of an
8". Same speed, same data transfer rates, etc.
As for the index hole, this wasn't such a bad
thing unless you wanted to
use 'flippy' disks in an ATR. Atari drives don't use the hole at all so
flipping the disk works fine. With the ATR as a controller though you
have to punch another index hole in the disk or use a standard mech with
dual sets of index hole sensor such as those 'flippy' drives made by
Pertec and Aerocomp -never seen em', I just know they made them.
Ah, yes.
I manufactured and sold a jig for marking and punching. The first product
that I had that ever got any free ink (in Dr. Dobbs)
And then there are these freaky 3" disks I have
for an Amstrad I once
owned.....
Nice, aren't they?
But, if you have a DS drive, then it won't let you flip the disks (as you
could with a SS drive; thus resulting in an inability to read second sides
using a DS drive.
3.25" was another fun one. Pushed by Dysan, it was made like a
"normal" floppy.
--
Grumpy Ol' Fred cisin(a)xenosoft.com
9:27 a.m.
On Tue, 30 Oct 2001 UberTechnoid(a)home.com wrote:
Actually all Amiga HD drives, internal or external, work in
this fashion. They tend to be somewhat slow but I've never had any
more reliability problems with thier HD drives than with the DD
drives. Not too many of the HD drives around though.
Jeff
--
Home of the TRS-80 Model 2000 FAQ File
http://www.cchaven.com
http://www.geocities.com/siliconvalley/lakes/6757
I recall the Amiga having a high-density
external disk addon that ran at
1/2 speed so Commodore wouldn't have to include a faster fdd controller
chip. The bad news. The good news is that it worked on all Amiga
machines right out of the box.
How was reliability for it? The Weltec half speed 1.2M 5.25" did NOT work
well. 
2:13 p.m.
XenoSoft skrev:
On Tue, 30 Oct 2001 UberTechnoid(a)home.com wrote:
> I recall the Amiga having a high-density external disk addon that ran at
> 1/2 speed so Commodore wouldn't have to include a faster fdd controller
> chip. The bad news. The good news is that it worked on all Amiga
> machines right out of the box.
How was reliability for it? The Weltec half speed 1.2M
5.25" did NOT work
well.
First of all, they're /slow/.
There is also a problem arising due to their slow rotation speeds. They get
clogged up quite easily, so running a cleaning disk once or twice a year is
really necessary to prolong the lifespan of your expensive HD mechanism.
> And then there are these freaky 3" disks I
have for an Amstrad I once
> owned.....
Nice, aren't they?
But why al that extra space? The disc can't be oval, so why the rectangular
case?
--
En ligne avec Thor 2.6a.
Amiga 4000/040 25MHz/64MB/20GB RetinaBLTZ3/VLab/FastlaneZ3/Ariadne/Toccata
31 Oct
31 Oct
12:12 p.m.
In <959.704T1950T3135843optimus(a)canit.se>se>, on 10/31/01
at 05:13 AM, "Iggy Drougge" <optimus(a)canit.se> said:
>> And then there are these freaky 3" disks
I have for an Amstrad I once
>> owned.....
>Nice, aren't they?
But why al that extra space? The disc can't be
oval, so why the
rectangular case?
I kinda wondered myself. Maybe the disks originally weren't intended to
FULLY insert into the drive but to hang out a ways for easier grasping?
They are 'flippy' disks so the designers probably anticipated a fair
amount of swapping.
The plastic band that pulls the metal shield back does need the full
travel to reveal the disk.
All in all, these seem much more rugged than the standard that won.
Regards,
Jeff
--
-----------------------------------------------------------
Jeffrey S. Worley
Asheville, NC USA
828-6984887
UberTechnoid(a)Home.com
-----------------------------------------------------------
30 Oct
30 Oct
2:09 p.m.
UberTechnoid skrev:
I recall the Amiga having a high-density external disk
addon that ran at
1/2 speed so Commodore wouldn't have to include a faster fdd controller
chip. The bad news. The good news is that it worked on all Amiga
machines right out of the box.
As I and Ethan Dicks stated last week. ;-)
To be nit-picky, the Commodore drive was internal, mounted in late A3000s and
all A4000s. Any external mechanisms were third-party.
--
En ligne avec Thor 2.6a.
Ky?suke: Jag heter Kurre, Kurre Carlsson!
Jag: Det heter du inte alls!
9:06 a.m.
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