
My Raspberry Pi Thinks It's a Mainframe - revorad
http://www.designspark.com/content/my-raspberry-pi-thinks-its-mainframe
======
iuguy
For those that are interested, the IBM Mainframe family is a fascinating
architecture, completely and totally with nothing in common with modern mid-
range or microcomputing.

MVS is the ancestor of a modern operating system, z/OS, also capable of
running on hercules, albeit with much more by way of hardware requirements[1]
(I wouldn't want to run it on a raspberry pi). IBM's licencing prohibits the
installation of z/OS on anything other than IBM mainframe hardware, which in
itself led to a bizarre situation where IBM, defender of open source projects
and patent abuse decided to start abusing patents against an open source
project[2]

[1] -
[http://www.youtube.com/watch?v=GRW4iPhCDSM&feature=relat...](http://www.youtube.com/watch?v=GRW4iPhCDSM&feature=related)

[2] - [http://arstechnica.com/information-technology/2010/04/ibm-
br...](http://arstechnica.com/information-technology/2010/04/ibm-breaks-oss-
patent-promise-targets-mainframe-emulator/) [2]

~~~
ctdonath
Long ago I found an IBM 360 emulator written in 2 pages of APL and published
in some technical magazine. Anyone recall this and have a copy? (I've found
websites with copies of similar articles, but lacked the straight-up APL
code.)

~~~
dandrews
You're not thinking of Falkoff/Iverson/Sussenguth's _A Formal Description of
SYSTEM/360_ , are you?
[http://www.cs.trinity.edu/~jhowland/class.files.cs2321.html/...](http://www.cs.trinity.edu/~jhowland/class.files.cs2321.html/falkoff.pdf)

~~~
ctdonath
Close, but not quite. As I recall (some 20 years ago) it had two pages of
actual APL code (not notation, real runnable code).

------
johnohara
The author's comparison doesn't really work. The power of those IBM mainframes
was in the entire architecture (SNA - System Network Architecture) not just
the processing unit. Terminals such as the 3270 talked to cluster controllers
that talked to batch controllers that talked to other controllers that fed the
processor etc. (simplified).

Data making it's way through the device chain was nothing for a 3 MIPS
processor with 64 MB of internal memory and 3MB IO to handle.

As far as IPL's were concerned, it was more common for the controllers to be
IPL'd than it was for the processor. Because of heat and cooling issues,
nobody ever wanted to shutdown the processing system or even let those boards
deviate much from their operational temperature. Bad things always happened
when they powered down and cooled off. Always.

Raspberry PI is better compared to a PDP-11, a VAX, or a Data General (Soul of
a New Machine).

~~~
farnsworth
Why would cooling off cause problems? Stories like this make me feel as far
removed from my computing ancestors as I feel from my farming grandparents.

~~~
sandfox
As chips / boards / etc cool, they move and contract and (massive
generalisation) this causes mechanical wear . I'm sure someone more versed in
such stuff can give a detailed explanation of what can happen. (there are lots
more side effects to power cycling gear as well)

------
dandrews
Couple of years ago I did this on my shiny new N900, and for a brief period
owned one of the world's smallest (if not _the_ smallest) MVS systems. Alas,
time marches on and that N900 seems rather old-school now.

~~~
seclorum
I once ported BCPL to the GP2X. BCPL came with an EDSAC simulator, so I used
it as the test app for the BCPL port .. so for a while, I had an EDSAC in my
pocket. ;)

<http://en.wikipedia.org/wiki/EDSAC>

<http://en.wikipedia.org/wiki/Gp2x>

XOX for the win!

~~~
eslachance
Guys, if you ever encounter a woman with a t-shirt that says "Talk nerdy to
me", I believe you will have her instantly jump on you and have wild sex, if
you tell her exactly what seclorum just said. Which, by the way, I have
absolutely no idea what it means. :|

~~~
eslachance
Hmn, erm... I guess that didn't quite have the comical impact I was hoping or
expecting.

My sincerest apologies to whomever this offended, it was absolutely not my
intention!

~~~
antoko
You should avoid the whole gender/sex angle and just make some comment about
extreme nerdiness.

"I'm a total a nerd and have been all my life I've been on HN for over 2yrs
and I can honestly say there's nowhere else on the entire internet where
people make comments that even come close to how nerdy yours does!"

That being said it still isn't that funny and it doesn't really add anything
to the conversation, but likely wouldn't have offended anyone either.

EDIT: forget to mention kudos for apologizing and not whining about downvotes
like most people seem to now.

~~~
eslachance
It's a personal challenge that I have, not to take offense or go on the
offensive and not taking it personally. A year ago, I would have reacted in a
completely different manner.

But you're right, "That is the nerdiest thing I have ever heard in my life"
would probably have been better. And yet, still not constructive in any way.
At least this little altercation _is_ constructive, at least for my attitude!

------
adestefan
While this is cute, a mainframe is so much more than just a CPU. The draw of a
mainframe is the support for massive I/O and bulletproof hardware.

~~~
Retric
Old school Manframes have poor IO by today's standards as in less than a mid
range wireless access point. And, the software and hardware where ridiculously
stable by today's standards but, if you look at mean time between failures in
therms of operations preformed not just time they once again fall behind.

PS: Still, to give an idea of why Manframes where considered such IO beasts a
high end PC's IO is about ~1000x as fast (HDMI is 10.2 Gbit/s + USB + Gigabit
Ethernet etc), but it's got ~1,000,000x the processing power.

~~~
sophacles
Of course, if you don't pretend that mainframes stopped advancing, you see a
different picture. Modern zSeries (or whatever new marketing they've come up
with) have multiple 10Gbit interfaces to a network, and can keep them all fed.
Not to mention special offload processors for AES and X509 certs, and of
course hardware partitioning and virtualization built in. Mainframes are still
pretty badass - a lot of stuff that is exciting and new in the server space is
stuff that IBM was doing for decades in the Mainframe space.

There is just something very cool about handling something on the order of
10^5 fully ACID transactions per second, while still allowing real time
database querying and on-the-fly hardware failure tolerance.

~~~
ori_b
The levels of hardware failure tolerance are amazing. I believe that hot swap
CPUs fit somewhere in that list, as does memory. (see the 'fault tolerance'
section here:
[http://www-03.ibm.com/systems/z/advantages/resiliency/datadr...](http://www-03.ibm.com/systems/z/advantages/resiliency/datadriven/server.html#design))

------
delinka
I'm surprised someone hasn't mentioned attempting to supplant IBM's older
mainframes with smaller units like Pi, Arduino or Bone. However, maybe it's
generally known that ... you can't. Because IBM has the same hardware/software
tying licensing arrangement that people decry Apple for having.

~~~
spitfire
What is bone? ddg search doesn't find anything easily.

~~~
winestock
He means the BeagleBone. It's an ARM-based single-board computer that fits in
a mint tin.

<http://beagleboard.org/bone>

~~~
dredmorbius
I've been saving mint tins for something just like this....

------
kibwen
_Shortly after our 3270 terminal attaches to Hercules the VM system starts to
boot, or “IPL” to use the IBM parlance._

Brilliant, I've wondered for a while now what my boss has meant every time
he's told me that they're IPL'ing the mainframe and that I'll have to remount
my exported NFS shares.

~~~
gaius
"Initial Program Load", which actually makes more sense than "bootstrap".

~~~
sammyo
If you had been around that generation of systems and toggled in a 30 byte
program in hex or octal that loaded a paper tape or card deck that then loaded
the actual OS, bootstrap seemed a reasonable term.

------
sethish
The [Hercules System / 360](<http://www.hercules-390.org/_> that the author
mentions and links to is maintained by [Jay
Maynard](<http://en.wikipedia.org/wiki/Jay_Maynard>), ROFLcon alumni and
better known as [Tron Guy](<http://knowyourmeme.com/memes/tron-guy>).

------
ericmoritz
A really neat project is the Erlang Embedded and a parallel project, Nerves.

I imagine a little cluster of these things in my house :)

<http://www.erlang-solutions.com/news/1/entry/1307> <http://nerves-
project.org/>

------
m0nty
But still you can't actually buy a Raspberry Pi ...

~~~
Karunamon
Sure you can, you just won't receive it for 2-3 months ;)

~~~
m0nty
It's disappointing :( I work in education and would like to try this thing out
for a variety of projects, but the delays in getting them to market mean I
probably won't get one. There are alternatives, not least (for the very
interesting original article) just setting up a Linux box and using Hercules,
etc, on that. It's a real shame that supply problems risk putting a damper on
the huge public interest and enthusiasm for the Raspberry Pi.

~~~
ssmall
Its disappointing in the short term, but look at the big picture. All this
extra interest and purchases from the private sector if handled correctly will
let them buy in bigger bulks, twist more arms in manufacturing, and find and
fix more bugs. In the long run getting this boards out to a wider audience
will give you a more stable, feature-rich and cheaper product.

~~~
m0nty
I hope that will be the case. My ultimate motivation is to get students
interested in programming and all the other things (control tech, etc) a cheap
expendable PC can facilitate. I could easily get 20 of these if they were
available but getting one is tricky enough at the moment.

------
ticks
I have only recently started looking at the Raspberry Pi, one thing that
struck me was the use of SD memory for storage... I have used USB sticks to
boot Linux before and they only lasted a few months of continuous use. Perhaps
I'm missing something? Other than that I'm impressed, the device has lots of
potential.

~~~
anthonyb
Don't use a swap partition. That's typically the cause of early flash death. I
have an old EeePC 901, with 12GB of onboard flash - it's still going after 2-3
years of relatively heavy use.

~~~
bandy
Not swapping and getting rid of Linux's ridiculously noisy (for a personal
laptop) and duplicative logs and perhaps mounting with "-o noatime" will help
a lot as well.

Additionally, the SDD in your 901 isn't just a hunk of flash - it contains
additional logic that will perform Wear Leveling on the physical flash
modules, resulting in more write cycles before you see a failure. (Higher-
capacity thumb drives also have wear levelers to fight against the OS's
propensity to always allocate data sectors in the same order, but they're a
different variety than those found in SSDs, from what I've read)

------
diminish
What about a data center, consisting of millions of raspberry PIs?

~~~
arethuza
Are there any scenarios where this would be preferable to virtualization?

~~~
av500
If you are an ARM shareholder

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its_so_on
It's always amazing to see how people computed in the time of Dickens and
Edgar Allan Poe.

just kidding...but I can't help but wonder if even the people who are kids now
will realize this stuff isn't from the nineteenth century... I mean, just look
at the device you're reading this on :) We've come a long, long way.

~~~
jerf
"It's always amazing to see how people computed in the time of Dickens and
Edgar Allan Poe." - Then you'll love
<http://www.youtube.com/watch?v=4rzAL5YwFow> .

~~~
chime
Thanks for the video. Can't wait for jgrahamc to build it.

