On 2011-07-02 11.57, Mark Benson wrote:
On 1 Jul 2011, at 17:37, Johnny Billquist wrote:
On 07/01/11 09:33, Mark Benson wrote:
On 1 Jul 2011, at 07:46, Johnny Billquist wrote:
RA92 is 1.4G.
I think 1.6GB is the unformatted size, 1.4GB after initialize.
Well, the unformatted size is actually even bigger, at around 1.9G. But who cares about
that? It is not something you can ever see or use.
Is it important for the size of the RAW virtual disk though? I haven't established of
the virtual disks in SIMH need to be large enough to contain the unformatted size of the
disk they are emulating?
No, they should not. The raw unformatted size is not something that is *ever* visible
outside of the disk, and when you emulate the disk, you are not emulating the unformatted
magnetic platters, but a block formatted device.
Since SIMH creates standard disk files itself I guess it's not a big issue. I am just
curious though.
Curiousity is good. The thing you emulate is the thing that is visible at the disk
contoller layer. So anything beyond that will (probably) be different from the thing you
emulate. When you emulate a uVAX with an RA92 disk, simh will present you with a emulated
KDA-50, on which there appears to be an RA92 connected. In the real world, the KDA-50 runs
some sort of microcode, and communicates with the disk over SDI, which is a serial
protocol using four coaxial cables. And the SDI protocol defines how the KDA-50 gets the
RA92 to do all kind of operations.
But none of that is emulated, and there is no real point in emulating it. From the VAX
point of view, you have the MSCP interface, as implemented by the KDA-50. And the emulated
KDA-50 also gives you the MSCP interface. What happens beyond that is irrelevant, as far
as the VAX is concerned. If it responds like a KDA-50 with an RA92 to the MSCP commands,
then the VAX is satisfied.
And at that level, the RA92 is only going to show you 1.4G of disk. Always. Other
properties are also true at this level. For instance, there are never any bad blocks.
And it's 1.4G after formatting, not initializing. (Atleast in DEC speak, where
formatting is the low level formatting of the device, and initializing is creating a file
system.)
Oh, okay. Fair point, I gotten used to stuff coming low-level formatted over the years.
It's kind of a non-issue on modern systems! ;)
Not entirely. Sometimes you still want/need to do a low level format, but I agree that it
is not as common, perhaps. Not that you needed to do it that much in the past either, but
people still sometimes did, for various reasons.
[...]
So, you have a total blocks of 311200, which matches an RD54, yes. If your disk container
is much bigger, and you haven't somehow gotten simh to restrict it, the total blocks
number should match the hardware, so this would suggest that you got something wrong
outside of VMS.
Yes, I agree the screw-up is in the SIMH config. What I'm not sure about is why SIMH,
which had the disks configured as RAUSER (i.e. a user-defined size) value of 9600000
blocks (4.8GB at 512bytes per block) then reverted to using RD54 174MB disk sizes... odd.
Perhaps I got the SET command wrong in the vax.ini I wrote, or SIMH interpreted the
command wrong. I don't know.
It doesn't matter for now, I'm working with 3 RA92 images that do display the
right capacity and I am up and rolling. I can telnet to a separate IP at any time and log
right into VMS.
I don't know if this is a purely semantic point (i.e. because the security risk is in
real terms negligible given it's a hobbyist machine) but should I be concerned about
only having TELNET and no SSH? I used the Compaq TCP/IP 5.1 off the 7.3 CD-ROM. Someone
mentioned a later version maybe? Does that have SSH?
Good to hear things are working now.
As for telnet vs. ssh. Well, ssh is safer, in that people can't sniff passwords easily
over the network. If you worry about people doing that, then you might want to not use it.
However, if your network is secure, then telnet isn't really an issue.
I don't think that Compaq have any version of SSH for VMS om VAX, but I haven't
checked if anything was shipped after 7.3.
There are other options, though. tcpware comes to mine.
Johnny