4 Jun
2012
4 Jun
'12
10:13 a.m.
On Mon, 4 Jun 2012, Jerome H. Fine wrote:
Just to add some complexity (or perhaps some
confusion) to the situation,
the RX50 from DEC uses DD floppy media, but if I remember correctly,
has 96 tpi. I know that on a PC, the HD drive is used to read and WRITE
the RX50 floppy media using John Wilson's program "PUTR.COM". In
Yes, you want use the "1.2M" ("dual mode") drive in 96tpi stepping,
but
but with "DD" (MFM,300RPM,250Kdtr) read/write. SOME of the 1.2M drives
refuse to do that, and INSIST on switching to 48tpi when in the "low
density" mode.
The RX50 has 800 blocks on one side for a total of
409,600 bytes.
If I remember correctly, the geometry is 80 tracks with 10 sectors
per track of 512 bytes per sector. Since the density is very similar
to a DD media from the PC, DEC was able to use that media on
the RX50. But I think there are 96 tpi (which requires the HD drive
on the PC) rather than 48 tpi which is what the DD PC drive uses.
right
96tpi "DD" is a drive that IBM never used in USA PCs. Outside of USA,
PC/JX model used it.
Such drives (Teac 55F, SA465, etc.) can be easily connected to a PC for
non-PC disk formats.
I I have any of the physical properties incorrect, I
apologize. I just
wanted to add a bit more information to the mix and note that
the RX50 media can be read and written on a PC, but MUST
use the HD 5 1/4" PC drives BUT with DD media 360K diskette
media - which is what the RX50 uses on the actual DEC drives.
I do not know if what the PC HD 5 1/4" 1.2 M drive using
DD 360K diskettes produces matches exactly what the actual
DEC RX50 expects, but it does work in practice.
It should.