It all started when the place I used to work at threw out a pile of old PC base units along with a big box of (unopened) Windows 98 disks !
I got as many PC's as I could carry for £5 each (OK, so they were Pentium MMX 233's with 16Mb of SIMM, a 3c509 (ISA) network card - but they all had CD drives and some had even been 'upgraded' to 500 Mb hard disk !). I also deprived the dustmen of the Win98se CD's.
What to do with this windfall ? - well I was already running seti on my 'home' PC and had heard of the DC Farm systems being put together in the USA so I decided to have a go too !
My first system was simply 8 PC's wired together with a low cost (10mbs) Hub - they all had hard disks but only one had keyboard/mouse/monitor - and this acted as the 'central store' = it had a dial-up Modem connection to the Internet and every night I would (manually) upload the 1 to 5 (depending on crashes etc) completed units and download some new ones.
In those days it took about 25-30 Hrs to complete each SETI work-unit :-)
This remained the same for about 6 months - then I discovered eBay !
The rest, as they say, is history.
A dozen or so old motherboards and an 18 port Hub later and I was building my very first 'Seti-Wall'.
Steve's first seti-wall (the yellow post-its are on the 'live' nodes)
The shelves where still being used for other things in those days, and I since I only had one 18 port Hub I was somewhat limited :-) - but I soon realized that fitting each new motherboard with a hard disk was going to be both expensive and noisy !
So I spent the next 6 months getting the system to boot Windows 98se from a network 'share' - all without the benefit of Microsoft's help (in fact their software seems to go out of it's way to prevent any such thing) and without using Windows Terminal Server (and paying more money to Microsoft).
By the end of 2002 I had two 8 port & one 32 port switch and although not all the ports are filled the wall is :-) - so those same old MMX 233 boxes are still doing service (OK, now they have AMD K6-III's inside, but it's still the same old boxes).
So how did I do it?
You can either read the FAQ below or dive straight into the How-To (or view the Changes since 2002 page)
You can aslo see how I later used CF sards (and USB sticks) as boot devices Booting from CF card (and USB stick)
FAQ
(everyone should have a FAQ)
1) Microsoft says Windows 98 can't (won't :-) ) run from a RAM disk ?
3) What about the Windows boot Registry set-up sequence ?
4) How can you run networking in Windows with the 16 bit drivers loaded by DOS ?
5) But running from RAM disk means nothing gets 'saved' after a power-outage !
6) Why use a Switch (and not a Hub) ?
7) What's the best Processor for seti ?
8) What did it cost to build ?
10) What's it all cost to run ?
11) What does the 'other half' think about it all ?
A) A typical 'node' with motherboard (on-board video), network card, (small) PSU and boot floppy.
C) 'Seti Wall' - the View from the door
D) 'Seti Wall' - the View from the 'command console' !
Answers
1) Microsoft says Windows 98 can't (won't :-) ) run from
a RAM disk ?
"So why can't Windows detect that it's running from a RAM disk ?"
Windows doesn't know it's running from a RAM disk. It thinks it's running from a Compacted hard disk. At floppy boot time, both the RAM disk driver and the (16 bit) Compaction driver load well before Windows even thinks about getting started. So all attempts by Windows to access the 'physical' c:\ drive have to go via the Compaction driver - which in turn goes via the RAM disk driver !
"But wait a moment - booting into DOS and booting into Windows involve totally different processes (DOS is 16 bit, Windows 32 bit) - surly there's no way DOS can suddenly switch over to Windows ?"
Although Windows is a 32 bit operating system, it is running 'on top of' DOS - and although the boot processes are indeed different, 'win.com' does the trick of 'launching' Windows from DOS. This, by the way, is not true for NT or 2000 - these are 32 bit o/s with non-DOS boot sequences (and there is no such thing as 'NT.com').
3) What about the Windows boot Registry
set-up sequence
?
"OK, I've heard about win.com - but I know for a fact that 'Windows DOS' is not the
same as 'DOS DOS' - amongst other things, Windows 98 'DOS' mode prepares for
later 32 bit running by examining the Motherboard BIOS and hardware during the
Windows DOS boot-up sequence and creating values for the Registry to pick up later. So why doesn't
the Register initialisation process get 'upset' and cause Windows launch to
fail ?"
No idea - maybe because the 'Node image' was created on the 'Node hardware' itself and since good old Windows 'Plug & Pray' is just about able to 'cope' with being moved to a different motherboard, perhaps, when no values are found, it just drops back to the 'last used' set (which, of course, are OK since it's actually still on the same hardware) ?
4) How can you run networking in Windows with the 16 bit
drivers loaded by DOS ?
"Windows needs Windows network drivers .. how can it cope with DOS
drivers ?"
The 16bit DOS network drivers are unloaded from RAM when the 'net stop' command is issued. So when Windows launches, no network drivers are present (and IFSHLP will have 'reserved' the crucial low RAM for Windows to use).
5) But running from RAM disk means nothing gets 'saved' after a power-outage !
"Isn't it all a bit pointless ?
the RAM disk contents are lost every time the power goers out - so how do you
ever get any results ?"
True - RAM contents are indeed lost when-ever there is a power interruption.
This is why you have to install SETI on the mapped 'share' drive - that way your 'work in progress' is saved to the 'Server' hard disk on the
Node network 'share' and NOT on the RAM disk !
6) Why use a Switch (and not a Hub) ?
"I note you have switched to switches .. what advantage does this give ?"
This was only because I got the 10/100 Switch cheap on eBay at the time I was moving from
a 10mbs network to 100mbs.
With a 100Mbs network, you aren't going to see much difference between a switch
& a hub (in fact, a hub might even be faster since there is going to be some overhead as the
switch
decides 'where does this packet need to go ?').
NB. The only reason for going 100mbs was to speed up the boot process (moving a 30Mb 'image' across the network is reduced to a few seconds) - SETI wu's (work units) are only about 256kb each and each Node only needs a new one to process every day or so :-)
7) What's the best Processor for seti ?
"I've heard that SETI depends heavily
of the FPU efficiency .. and some vendors CPU's give odd results ?"
1) Quick answer = the 'best' CPU is whatever is cheap on eBay :-)
[the follow was true
late 2001/early 2002 when this was first written]
2) OK, Pentium III's are best, AMD K6-II are the worst (they have crap FPU (Floating
Point Units)
Today's (2002) AMD chips are much better (however they also need fancy DDR RAM and such like ..)
- so
the Pentium range (PII, III & Celeron) still wins.
3) As of today (November 2002), the best 'bang for the buck' is, without doubt,
the 1GHz Celeron (you can get them at 30 to 40 quid) - their 100MHz FSB also means
a
cheap motherboard (133 Mhz is faster but not significantly enough to warrant the additional cost).
4) The Intel Xeon chip used to be "The God of Seti 'crunching' " - but with the current
3.03 SETI Client
the big Xeon L2 cache no longer makes much difference and they are no longer
worth
the extra cost (nor the massive extra cost of the motherboard).
(2006) Funny enough, when HyperThreading came out, the Xeon chips suddenly become desirable again (2 SETI threads could be run at the same time and, together with 'cheap' Xeon motherboards from ASUS, the extra cost was well under the cost of 2 'normal' Nodes. However Windows 98 never supported multi-CPU configurations (or HyperThreading) so I never moved over to Xeon's "on the Wall".
8) What did it cost to build ?
Very approx (2002 prices) :-
Motherboard = £20 (average)
128Mb RAM = £12
PIII 450/Cel 533 = £28 (average)
Heat-sink & fan = £5 (must have good quality fans - they make less noise !)
PSU = £5
3c905c = £3 (approx - I got 12 for 30 quid)
Floppy drive (new) = £7
FD, net & PSU cable = £3 (£1 ea from the Computer Fairs)
98 Licence = £0 (Computer Fairs / eBay will have Windows98se at anything from
£20 to £50)
==
Total approx = £83
Add in 'part costs' (Switch, Server, KB/Mouse/Monitor/KVM), a few 'premium' parts (a couple of £35 1GHz Celeron's) and 'wastage' (blown motherboards) and you get a 'ball park' of ...
.... 'less than £100 per node'.
9) What about power ?
Use PSU's that are as small as possible - the more unused watts you have the
less efficient the PSU is at producing the watts you are using (and hence the
more heat) - I have mainly used 135watt units picked up by the 'box load' at
Computer Fairs (no-one wants them & you can pay less than £5 each
if you buy a dozen at a time ('Tell you what, how about 50 quid for the whole
box ?' ).
WARNING - make sure your PSU's are NOT 'system pulls' = check VERY carefully that they are 'brand new' / 'old stock' / 'un-used' ... PSU's are usually the first thing to go wrong with any PC - get some 'used' PSU's and you WILL end up 'frying' a motherboard/CPU or two whilst trying to work out which are the 'duffs' (I know, I did :-) ).
NB - for those of you with fancy 'Earth Leakage Detector' house Mains power circuits (ELCB's, RCD's etc) - playing with all those switch mode PSU's you are going to 'trip' your house power about once a month - this can be a real pain !
I now run mine on it's own protected 'spur' before the main trip - when they trip, they only take out the 'seti wall'.
10) What's it all cost to run ?
1) I don't like to think about it :-)
2) I save money on the heating because my seti-wall keeps the house warm ...
11) What does the 'other half' think about it all ?
1) I don't know - I never see her during the week and at weekends we are far
too busy :-)
2) But the cat loves it (all those nice warm boxes to lie on).
12) Anything else ?
Get it insured - also get Smoke Detectors.
A) A typical 'node' with motherboard (with on-board video - the network card is in the last slot to the right) with small PSU and boot floppy. The 'post-it' note shows that this Node has an AMD K6-III-333 CPU and processes each SETI wu in 33 hours (these AMD chips had really crap FPU's BUT they were cheap and could be used in existing motherboards :-) ) .
B) OK, not all nodes are diskless ! The big box on the floor to the left is the 'server'. Next (starting under the table) are the old MX233 boxes. Note also the manual 4 way KVM switch (behind the mouse mat) - this saves moving cables all the time during testing
C) The 'Seti Wall' - a view from the study door
D) The 'Seti Wall' - a view from the 'command console' !
Goto :- How To page
Goto :- Changes since 2002
Sept. 2001-2002.