19 Feb
2019
19 Feb
'19
6:24 a.m.
On Feb 18, 2019, at 10:29 PM, Warner Losh via cctalk
<cctalk at classiccmp.org> wrote:
On Mon, Feb 18, 2019 at 6:18 PM Bill Gunshannon via cctalk <
cctalk at classiccmp.org> wrote:
That's not correct.
RX50 is 80 track, single sided, 10 sectors per track (not the PC-standard 9 per track).
All tracks are 2:1 interleaved. There is a 3 sector skew from track to track. And
logical track 0 is physical track 1 (physical track 0 is logical track 79).
The MSCP controller does this; on a Pro it's done in the driver. I've done it for
RSTS, but it's easy to confirm by reading the source code of DEC drivers such as the
one in RT-11.
paul
...
No, RX50 was a strange DEC format. RX33 is a 1.2M floppy.
The RX50 was a single sided 800 block floppy. The first two tracks had no
interleave. The rest has 2:1 interleave, though sometimes physical and
other times logical. Strange in some ways, kinda standard in others. But
it's still a floppy, and other than size, much like the RX33 with 1/3 the
number of blocks.
Warner