Andrew Wiley wrote:
On Wed, Mar 25, 2009 at 5:44 AM, John Summerfield <
[email protected]> wrote:
Okay, here is what I think.
Count the cost.
Do you get a full, working system? If not, there are extra costs for the
bits that are missing.
We're still trying to figure this out, hopefully we'll get a response soon.
Depending on the capabilities of your particular machine, you will have
some number of essentially discrete systems (your LPARs). I gather any
hardware reconfiguration you do involves pinching a bit off one machine
to give it to another. Whether it's enough is for you to judge.
Who is going to do the reconfiguration management?
I'm not sure what you mean. As for setting up LPAR's, I expect that at some
point during the summer, myself and a few advanced students that are
Have you ever seen a computer that didn't require reconfiguring from
time to time? Even if setup perfectly, requirements change.
interested would spend as much as a week going through manuals, figuring out
how to get everything set up, and actually setting it up. That would cover
the software side.
As for the hardware, I'm going to have to make sure we have everything we
need either when we receive the system or shortly after.
Does this system have special power requirements? What about
environmentals?
We have a room (really a large, climate controlled closed) that houses some
servers (not many though), and we expect that we could probably put it in
there. We'll have to get some specifications on power draw and heat output
and run them past the maintenance department though.
What will be the cost of transporting the system and doing the initial
installation?
We're not entirely sure how this will work at the moment. It would depend on
how much care transporting a mainframe requires, which I haven't read about
(so far).
What have I forgotten?
Well, from the one datasheet I managed to find on the IBM website about this
machine, the hardware specs a company could buy vary (by today's standards)
from useless to excellent. If the company purchased a lower end version, it
wouldn't be worth the effort to get it transported and running.
There is a case for a central server to coordinate students' work. I am
not convinced that a mainframe, even a free one, is the best tool for
the job.
My contention is that if it's available, I can run linux on it, and it has
the capacity for what I need, it's the best tool for the job. As I explained
earlier, there are also some educational benefits to having a mainframe
rather than another system.
The only concern that I don't think I've voiced so far is maintenance. I
know it was mentioned that this machine would be close to the end of its
lifespan, and when maintenance costs become too high, I would have to find
another solution elsewhere. If this machine is already nearing the end of
its lifespan, I'll have to decide whether the effort of moving it and
setting it up is worth the estimated service life.
If a commodity PC requires more RAM or more disk, the most probable
upgrades, I can buy them from the local pc shop for tens of dollars and
install them myself. The whole thing could be done in half an hour,
including the shopping trip.
For any programming students might do, it makes not a jot of difference
whether they do it on a PC running Linux or a mainframe running Linux,
the tools are the same.
Since you said the students would be connecting
via ssh, I expect they already have PCs. The only Windows ssh client I
have used is putty, and while I will continue to use it, I don't like it
that well. To do the job properly, one needs Linux (or, I expect one of
the BSDs or a real Unix). If installing Linux on the student PCs'
hardware is frowned on, how about Linux inside VirtualBox (my current
favourite) or one of the MS free offerings.
What I'm looking at is using our existing Windows lab (the client computers
all run Eclipse and a few other IDEs) but storing code (SVN), providing
project management software, and allowing for a centralized testing location
for server software on a centralized server. I've never had a problem with
Putty, and some of the students use it. Connecting can be clumsy, but beyond
there, I haven't had any complaints. I like it more than I like the DOS
prompt.
Personally, I like to sit down at a virtual console. Generally, I have a
display that is 160 characters wide, 64 deep.
I like the idea so well that I configure my systems to have twelve of
them, X runs on tty13. I often use screen too.
From there, I ssh to whichever computer I need to work on, and it's
often the other side of the Internet.
Apart from a little latency (and a problem with phone lines over there
at the moment resulting in a lot of latency surrounding disconnexions),
there's no difference between local and remote computers (other than
anything related to the distro).
If I use putty from Windows, it seems to me that my experience is
limited to poking that box over there, I'm still using Windows.
This might give the students the same kind of setup so many free
software hackers have, their own PC and a central repository.
This does not preclude students from using virtual mainframes (hercules)
and checking out Linux on that.
It seems to me that, if you want the students to learn to appreciate the
benefits of a mainframe, you really need a full set of software too,
including representatives of the VM, OS and DOS families. While there
are free versions (I think I found VM on three 3330 images somewhere,
and I have MVS 3.08 around here someplace), they're pretty archaic.
This all comes down to what I can get my hands on. At this point, I don't
know what I would wind up having.
If all you have is Linux running on the bare metal on a mainframe,
there's little to distinguish it favourably from a PC.
Well, even in it's old age, this machine, if it had higher end
specifications at purchase time, looks like it could outperform pretty much
all the servers we run right now. Hopefully that's not a false impression I
got somewhere.
That would depend on the workload. If the students are building
significant software packages, the existing hardware might do better
than you think.
--
Cheers
John
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