13 Jun
2013
13 Jun
'13
11:45 a.m.
[Cutting extra slots i nthe sectorign ring]
Right... No, I didn't realsie it would autom,atically detect the original
type of disk,
I am pretty suree I have the machines to do it...
Anyway, as I said last night, it might be possible to machine off the
notched rign form a normal hub nad fit a new ring wit hthe right number
of notches. That would mean you could make 16 sector disks.
Ah... My time is free. Or at least nobody will pay for it.
If I had the equipment I'd try to do it. But I don't have it. I have only a
A small lathe/mill is something to consider. Be warned, thoguh that you
will want ot buy/make a lot of add-ons, and that learning to use it well
take a long time. And that it quickly becomes addictive (hmmm... Like
computers, I guess).
-tony
That would be possible for 12 to 24 slots only. My
primary goal is to have 16
Sure. As I mentioend, that is one that I do want to make. I have this
mad idea of putting together a complete HP9880 system for my HP9830.
For those not into old HP 'calculators', the HP9880 is the disk system
for the HP9830. It consists of a number of units :
HP11305 controller (a failry complex microcoded thing)
HP11273 'cable' to link the HP9830 to the controller. This 'cable' ahs a
PCB at each end with about 25 chips on each PCB. The sector buffer RAM is
one one of the PCBs, for example. In fact uo can plug 4 such cabels into
oen controlelr to chare it between 4 HP9830 machines.
HP11273 ROM module. This fits in the HP9830 and contains the bootstrap, etc.
HP11302 'cable' to link the controlelr to the disk drive. This has a PCB
at only one end and contains mostly signal buffer ICs
HP7900 drive. This is a twin-platter thing with oen fixed platter and oen
remvoable pack which is similar to an RK05 pack. The drive has 4 heads on
oen carrage and thus can onlt be used if there is a removable pack in
place. There's a separate sectore sensor for each platter, the one for
the fixed platter is set up for 24 sectors (25 slots total in the ring),
the 11305 assuems this (although it takes sectors in pairs...). So the
removabel pack ahd better be 24 sector too. Unlike the RK05, the
comaprison of the cector counter is done in the drive -- the controller
loads the wanted sector number into a register in the drive and there's a
signal from the drive to the controller that is asserted when the sector
counter (reset by index, ioncrements by sector) has the right value.
A PSU (I forget the number) for the drive
The removable pack
A casette containing teh OS that is copied to the disk on initialisation.
So far I have alsmot everything. THe only things I am missing are the
correct 24 sector pack and the PSU for the drive. Alas my drive needs a
lot of work to get it going again (I hope the heads are OK...) but I
intend to give it a go.
For tesitng the drive shoudl spin up with any pack in the drive. Since
the fixed paltter is alsways 24 sectors I cna test with that. But a
remvoeable pack would be nice too.
sectors AND I don't have a mechanic shop. And no
access to someone who
just does it for me.
YEs, I guess a mill and dividing head are not all that common....
Actually, that is an issue with modifying the
drive rather than the pack.
A modified drive can;'t read 'original' packs, and the packs recorded on
the modified drive can't be read on an unmodified drive. You cna't
exchange packs with friends unless they also have the modification
fitted.
Hm. Not sure if I was clear enough:
A modified drive can use original packs as well! The modification will step
aside if it detects that the used pack already has the desired sectoring.
A soft re-sectored disk from a modified drive can't be read on an unmodified
drive, of course. Modifying the
drive would thus appear to be a lot more practical for 16
sector machines.
For HP 24 sector ones, cutting the extra notches
seems
quite possible.
ONLY for that case IF you have access to the equipment needed. But
then: Yes, of course! > cost would be the programming and setup of the CNC
that turns the hubs. Then
Can't anyone turn by hand any more?
If you want *one* piece or two pieces... Then you might pay for the labour. But