[rescue] More IBM emulation fun

[Geoffrey S. Mendelson]

On Tue, Feb 10, 2009 at 08:07:33AM +0000, Mark Benson wrote:
>
>Okay I got as far as booting Hercules, and it seems to pick up all the  
>tapes and start up. The first part of the ReadMe that comes with
>Bob Abeles VM/370 R6 distro requires you to open a new terminal and  
>'telnet localhost 3270' then on the Herc type 'ipl 580' (presumably  
>this connects the telnet session??). I get the telnet to connect but  
>on trying 'ipl 580' (Enter) I get:

Ok, you need to start at some mainframe basics. The IBM 360 and the early
370 computers had a console with blinking lights and a selectric typewriter
terminal. It was address 9 or 15 on channel 0. The later 370s had a 
3270 display console, I think at address 15. You could also boot using
a different 3270 console. 

Telneting to the hercules program connected your terminal session to
the program. It would have to be in console (3215) mode.

Assuming hercules is running on your Mac, then you would telnet localhost
with the specified port. Note that hercules has to be running in order for
the telnet command to "stick", otherwise the port won't be accepting
connections.

You will come across this later, as you have to be able to issue commands
to CP instead of your virtual machine. CMS can be set to pass commands it
does not understand to CP, but if it is not waiting for a command, you
have to interrupt your VM and type the command.

If you are using a 3720 terminal, it will display "CP Read". Depending upon
the setting of "run" CP will pause your VM or not. Normally in your profile
file for CMS you had a "cp set run on" in it, and I think it could be 
specified in your directory entry for a VM that did not run CMS.

IPL stands for inital program load. It means that the first block of
data from the device is read starting at memory address 0. When the read
completes, the cpu starts executing at location 0.

On a real 360/370 with switches, you had dials on the front you set
to the IPL address. Later 370s, you typed an IPL command on the hardware 
console. VM allowed you to specify a device, and so does Hercules.

In order to boot using an "IPL 580" command, you have to have a device
defined at address 580 (device 80 (hex) on channel 5), and have the proper
IPL program on it. 



>
>HHCCP029E ESA/390 mode IPL failed: CSW status=0020
>            Sense=00000000 00C00300 00000000 00800100 010000FF FF000000

A quick guess is that the virtual computer you are trying to boot is either
in ESA mode, not 370 and/or there is no device at 580. If I remember my
hercules correctly, this means there is no config file. The config file
will define the processor mode AND allocate device addresses to files.

BTW, wasn't there a 4 pack VM system, all ready to go? You just download 
and unpack it. It had everything set up to run. 


>Of course, the error codes mean nothing to me. Just wondered if you'd  
>run over this issue. I'm also using OS X 10.5 Intel.
>
>This is fun... no really!

VM is fun, MVS is interesting. (as in may you run an interesting operating
system). :-)

Geoff.

-- 
Geoffrey S. Mendelson, Jerusalem, Israel gsm at mendelson.com  N3OWJ/4X1GM