7 Nov
2001
7 Nov
'01
11:36 p.m.
That spiral cam was an attempt to reduce price and mass, I suppose. Like the
stone wheel, I imagine it was better than SOME of the other options available at
the time, in one respect or another.
I don't remember at all (go figure!) what options there were at the time, short
of the lead-screw that was used on 8" drives, for moving the heads. I've got a
few pictures of Siemens mini-drives (5-1/4") that use lead screws, but I don't
remember other vendors using them. Did Shugart make a minifloppy with a lead
screw? The old BASF drives that I've cussed from time to time for their
fragility at the door latch used that spiral cam arrangement. It was
interesting, and, if you worked at it, you could foul it up, since it was
readily accessible. Every other scheme I remember from that period used a
tendon drive, as did the DS 8" drives, other than Siemens'. What do you
remember?
Dick
----- Original Message -----
From: "Don Maslin" <donm(a)cts.com>
To: <classiccmp(a)classiccmp.org>
Sent: Wednesday, November 07, 2001 9:57 PM
Subject: Re: Apple Floppy Drives (was: More Apple Pimpers)
On Wed, 7 Nov 2001, Eric Chomko wrote:
it!
Allison wrote:
And worth every penny of it :) But the fact is, that despite your
fortunate experience, the spiral cam head positioner was probably the
worst idea since the stone wheel!
- don
> >
> > 2- horribly botched controllers (TRS-80 without mods)
> > 3- software such as disk drivers that would hang if no media or errors
> > 4- floppy drives/controlers that would "bite" the media on power
up or
> > down.
> > meaning it would write trash due to no write locks.
> > 5- not enough space
> >
>
> Considering the alternative to #5 was cassette or paper tape, we lived with
General comment,
Most 8" systems were expected be and behaved reliably and have
at least 250k of space.
Most 5.25" systems could be reliable but, often weren't. I'll restrict
comments to 5.25" for the later reason.
Most of the complaints I've had with disk systems be they Apple or not
were often in this order.
1- Drives (SA400 was pure garbage!!!)
Whoa! I bought my Smoke Signal Broadcasting disk system back in 1978
with two SA400 drives. I added a third drive in the late 80s. To this day
all three drives work great. I did switch drives 0 and 2 to allow the most
used drive to get less use and the newest drive to become the main drive.
But, I'd hardly call a disk drive "pure garbage" that has lasted for 12
and
23 years! And that is in lieu of the fact that they had a 5 year life
expectency.
my 2 cents... >
> >
> > The apple-II was plagued with #1 and somewhat with #3 depending on
> > OS and definately #4. Space was a problem for many users(#5)
>
> >
>
> > Trash-80 was 1 through 5 example.
> >
> > NS* mostly #4 had to be watched if the drives were seperately powered and
> > earlier units were SA400 (#1 problem). The SD controller while bullet
proof
> > was
> > space poor at 90k per drive (#5).
> >
>
> My SSB system was SS/SD soft-sector and had a whopping 80KB storage
> capacity per diskette. Didn't TRS-80, Apple II, Northstar and others ALL
have
> a different scheme (i.e. more capacity,
hard-sectoring, double
sided/density)?
My point is that, maybe they were trying to do to much with the little ole
SA400
than the thinhs was designed to do?
CCS used 8" disks and reliable controller. It was however prone to #4.
Many S100 system that used 8" drives and the better 5.25 drives fell
in this realm of reliability though most with 5.25 were pretty cramped
until 360k(DD) or 720->780k(QD aka two sided DD) formats were common.
By then CP/M and S-100 was dying.
Of the most reliable my AmproLB+, Kaypro 4/84 with Advent turborom,NS*
(both SD and DD) and most of the post 1981 systems in the commercial
systems space. My expectations of reliable were set by minicomputers
long before micros I'd worked with where if the disk didn't work it was
something I did wrong.
Mini computers had their fare share of disk problems too. The Interdata 7/16
systems I worked on in the mid-70s were slated to be outfitted with
floppy drives. They could never make them work. It was either hard disks
(20 MB system, w/10MB fixed and 10MB removable), or good ole paper
tape and TTYs.
Of all, my opinion is that floppies were ok but the first real improvement
was the 3.5" drives(720k and 1.44m generation) with the power fail logic
on board. They offered good storage, small size, lower power, good
reliability
and quieter than the whole lot.
And the fact that the 1.44MB floppy is STILL a standard device on many
systems to this very day.
Eric
Allison