Re: [TUHS] Booting PDP-11's from RX02's

2016-11-03 Thread Eric Smith
On Tue, Nov 1, 2016 at 3:53 AM, allison wrote: > On 10/31/2016 07:45 PM, Al Kossow wrote: > > > > On 10/31/16 3:08 PM, Vincent Slyngstad wrote: > > > >> Isn't there some weird crap in track 0 on DECmate RX01s > > It also has the slushware code, aka front panel space code to

Re: [TUHS] Booting PDP-11's from RX02's

2016-11-01 Thread allison
On 10/31/2016 07:45 PM, Al Kossow wrote: > > On 10/31/16 3:08 PM, Vincent Slyngstad wrote: > >> Isn't there some weird crap in track 0 on DECmate RX01s It also has the slushware code, aka front panel space code to do stuff on the IM6100 chip and peripherals. the 6100/6120 have two spaces front

Re: [TUHS] Booting PDP-11's from RX02's

2016-10-31 Thread jim stephens
On 10/31/2016 12:41 PM, allison wrote: On 10/31/16 3:26 PM, Paul Koning wrote: On Oct 31, 2016, at 2:58 PM, jim stephens wrote: If you cared about not erasing the drive manufacture's data on sealed media Winchester and the like you have to avoid any writes to cylinder 0

Re: [TUHS] Booting PDP-11's from RX02's

2016-10-31 Thread Fred Cisin
If you cared about not erasing the drive manufacture's data on sealed media Winchester and the like you have to avoid any writes to cylinder 0 at all. On a floppy? It might not be relevant HERE, but SOME computers have a different physical format on track 0 (such as systems that evolved from

Re: [TUHS] Booting PDP-11's from RX02's

2016-10-31 Thread Al Kossow
On 10/31/16 3:08 PM, Vincent Slyngstad wrote: > Isn't there some weird crap in track 0 on DECmate RX01s It is IBM 3740 table of contents information. GA21-9182-5_Diskette_General_Information_Manual_Jul80.pdf for the details

Re: [TUHS] Booting PDP-11's from RX02's

2016-10-31 Thread Vincent Slyngstad
> From: Don North > Track 0 is not used by standard DEC software I wonder why DEC did't use track 0. The thing is small enough (256KB in the original single-density) that even 1% is a good chunk to throw away. Does anyone know? (I had a look online, but couldn't turn anything up.) Isn't

Re: [TUHS] Booting PDP-11's from RX02's

2016-10-31 Thread allison
On 10/31/16 3:26 PM, Paul Koning wrote: On Oct 31, 2016, at 2:58 PM, jim stephens wrote: If you cared about not erasing the drive manufacture's data on sealed media Winchester and the like you have to avoid any writes to cylinder 0 at all. The drive formatting software

Re: [TUHS] Booting PDP-11's from RX02's

2016-10-31 Thread allison
On 10/31/16 2:58 PM, jim stephens wrote: On 10/30/2016 4:24 PM, Don North wrote: On 10/30/2016 5:47 AM, Noel Chiappa wrote: > From: Don North > .. the hardware bootstrap reads track 1 sectors 1, 3, 5, 7 Ah, thanks for that. Starting to look at the code, I had

Re: [TUHS] Booting PDP-11's from RX02's

2016-10-31 Thread Paul Koning
> On Oct 31, 2016, at 2:58 PM, jim stephens wrote: > > If you cared about not erasing the drive manufacture's data on sealed media > Winchester and the like you have to avoid any writes to cylinder 0 at all. > > The drive formatting software could read that cylinder track 0

Re: [TUHS] Booting PDP-11's from RX02's

2016-10-31 Thread jim stephens
On 10/30/2016 4:24 PM, Don North wrote: On 10/30/2016 5:47 AM, Noel Chiappa wrote: > From: Don North > .. the hardware bootstrap reads track 1 sectors 1, 3, 5, 7 Ah, thanks for that. Starting to look at the code, I had missed the interleave. So does DEC do

Re: [TUHS] Booting PDP-11's from RX02's

2016-10-31 Thread Pete Turnbull
On 31/10/2016 13:55, Noel Chiappa wrote: I wonder why DEC did't use track 0. The thing is small enough (256KB in the original single-density) that even 1% is a good chunk to throw away. Does anyone know? (I had a look online, but couldn't turn anything up.) If I had to _guess_, one possibility

Re: [TUHS] Booting PDP-11's from RX02's

2016-10-31 Thread Paul Koning
> On Oct 31, 2016, at 9:55 AM, Noel Chiappa wrote: > >> From: Don North > >> Track 0 is not used by standard DEC software > > I wonder why DEC did't use track 0. The thing is small enough (256KB in the > original single-density) that even 1% is a good chunk to throw

Re: [TUHS] Booting PDP-11's from RX02's

2016-10-31 Thread Noel Chiappa
> From: Don North > Track 0 is not used by standard DEC software I wonder why DEC did't use track 0. The thing is small enough (256KB in the original single-density) that even 1% is a good chunk to throw away. Does anyone know? (I had a look online, but couldn't turn anything up.) If I

Re: [TUHS] Booting PDP-11's from RX02's

2016-10-30 Thread Don North
On 10/30/2016 5:47 AM, Noel Chiappa wrote: > From: Don North > .. the hardware bootstrap reads track 1 sectors 1, 3, 5, 7 Ah, thanks for that. Starting to look at the code, I had missed the interleave. So does DEC do anything with track 0, or is it always just

Re: [TUHS] Booting PDP-11's from RX02's

2016-10-30 Thread Noel Chiappa
> From: Don North > .. the hardware bootstrap reads track 1 sectors 1, 3, 5, 7 Ah, thanks for that. Starting to look at the code, I had missed the interleave. So does DEC do anything with track 0, or is it always just empty? Noel

Re: [TUHS] Booting PDP-11's from RX02's

2016-10-30 Thread Don North
On 10/29/2016 2:32 PM, Ron Natalie wrote: I think just like everything else the boot rom just pulls in the first sector of the disk. I had RX02s on many of the BRL Gateways (my implementation that replaced your MIT Gateway while you were in exile). We put a V6 file system and I must have had a

RE: [TUHS] Booting PDP-11's from RX02's

2016-10-30 Thread Ron Natalie
I think just like everything else the boot rom just pulls in the first sector of the disk. I had RX02s on many of the BRL Gateways (my implementation that replaced your MIT Gateway while you were in exile). We put a V6 file system and I must have had a regular V6 boot block on it with a RX02.