24 Jan
2013
24 Jan
'13
11:13 a.m.
On 1/24/2013 10:42 AM, Fred Cisin wrote:
On Thu, 24 Jan 2013, Dan Gahlinger wrote:
You are talking
apples and oranges here. He is citing the example of a
chip that is "defeatured" which means that the manufacturer makes one
unit and either enables the feature or removes it. Most tests would be
cheaper to test a common unit such as this overall and then defeature
the hardware on the unit to be priced lower later, and kick out all bad
media regardless of where the errors are.
The comparison he is making should be about that, not trying to extend
the yield on a process by cherry picking.
You are totally right a defect list is not just to cover excess
capacity, it should and must be a report of the defective spots on a
media type device.
I remember manufacturers selling SS and DS
5.25" disks for commodorethat
were actually all DS, just a disk notcher away from double the storage.
Yeah?
So, has anybody here EVER seen a 5.25" disk that was NOT coated
on both sides?
as for the 486SX (or was it 386SX)
NO, it
was NOT.
386DX was 32 bit; 386SX was 16 bit
486DX had an FPU; 4986SX did not have FPU
debacle, there was software thatcould
completely restore functionality.I think it was called above-board,
NOPE.
which had hardware as well as software,but on
many SX type systems it
was just software Actually if I remember correctly it was the 486SX CPUs
made by AMD
We are talking INTEL.
that could be "converted" into a 486DX
by a simple piece of
software.there were a bunch of tricks with software around those days
likethe AMD 486DX-80 and so forth this practice is continued to present
with cpu cores being disabled,even though there may be nothing wrong
with them.
"Nothing wrong with them"
The MANUFACTURER says something is DEFECTIVE.
A user runs a TRIVIAL test, and declares that the manufacturer is WRONG.
Same thing wherein SPINRITE would "test" sectors DECLARED BAD by the
drive manufacturer, and SPINRITE would over-ride the manufacturer's
analog tests! After all, "3 successful read writes is a more reliable
test than 100 read/writes and measuring the signal amplitude!" Users used to replace the crystal in 5170s for greater
speed.
THEN, they would bad-mouth reliability of 5170.
DUH.
THAT is why IBM added boot code to refuse to boot with a changed clock
speed.
Our disk controller for the SMD used soft sectoring and could place the
sectors to the clock / bit for each sector on the track. We had an
extensive analysis program that would place the defects when discovered
in the gap between the start and end of our sectors, the largest gap on
the drive.
On SMD, however the manufacturers had a requirement that defects be 2
bits or more, or false address marks. any half or one bit errors, the
media had to be discarded or repaired. Also only a single defect /
track. I don't think our algorithm which is similar to the above would
work on floppies because I suspect they have more of the smaller errors,
and certainly could not assume a single error / track and work. This
still assumes with two errors a scheme could fit the required number of
sectors on the track, or the OS could cope with missing sectors with its
file system.
Most OS's seem to expect defect free media now days, and make no use of
file system level defect mapping anymore. I think that thread was
discussed some few months ago, won't rehash it here.
for commodore 64 again there was a utility
called "soft sector
format"which would format disks that had bad sectors, marking the bad
sectorsso you could use whatever good portions remained, for those of us
whowere too cheap to buy new/good disks.
It was sometimes possible, in the case of
physical defects, to move the
sectors around to try to get the sectors to not overlap the defects.
Every competent FORMAT program, even MS-DOS "FORMAT" will mark sectors,
blocks, or tracks bad and use the rest of the disk, unless blocked areas
were in unmovable locations (such as the Boot sector and DIRectory area).
Dan, you should be familiar with the software to
re-arrange and move
sectors to place the defect in the right place for Vault Pro-lock
copy protection. (paperclip scratch, and code looks for it).
NOTE: we are not talking about Pro-Lock-PLUS, which NEVER reached market,
although, to this day, gets blamed for misunderstood problems.
--
Grumpy Ol' Fred cisin at xenosoft.com