Cigartin sized Computing!

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A Little History:

Richard Brooksby has long had the idea for putting a computer in a standard-sized tobacco tin (about 120mm x 80mm x 20mm), with a connector (Ethernet, telephone, serial, or something else) on one or both ends. This is an esthetically-motivated project; simply having a small computer is insufficient; the computer has to live in an interesting enclosure. Think steam-punk. The hacker esthetic dictates that the computer be useful, of course, as (say) a server or network component of some sort.

Richard discussed this with Nick Barnes several times in early 1998. Some variations were discussed: solar power, parasitic power from a telephone line, piezo power from motion for a wearable device, a tiny LCD display similar to those found in mobile phones, digital cameras, etc.

The embedded systems manufacturers make a variety of computers which fit into small enclosures. There is a trend towards PC compatibility, which suits us because our inclination would be to run FreeBSD or a similar open-source PC operating system.

Of course, these days 200cc is pretty damn huge. Then Nick found a discarded cigar tin in CB1, a cafe which serves as a secondary office for Ravenbrook. This is around a quarter the volume (88mm x 83mm x 8mm) of a regular tobacco tin, and is a much more satisfactory challenge.

Then on 1999-01-26 Nick saw a reference to on Slashdot. And suddenly looks very plausible indeed...

Nick B


First, a little background. My original idea was to build a computer in a tobacco tin (not a cigar tin, which would be long and cylindrical). A tobacco tin for cigarette tobacco (e.g. "Old Holborn", which my Grandad used to smoke) is about 60mm by 40mm by 20mm. Originally I was going to get a low-power Z80 or 6502 type processor with some built in RAM and a UART and build something which was parasitic on the RS232 connector that would be on one end.

As time went on and technology got smaller the idea was refined and I thought of having a Unix host. These days it seems pretty easy and I think the challenge has gone out of the problem. Perhaps we could investigate a Unix host in a sygnet ring, or something.

I went to the first meeting of the Chicago FreeBSD Users' Group. Two other people were there. Jeremy McMillan was thinking of setting up a virtual private network running IPv6, in order to gain experience with the new networking standards. I'm quite interested in getting a really secure (and wire-tap proof) network going somehow.

Nick's original email:

The enclosure is 79 x 86 x 8 mm, with 6mm-radius rounded corners.

JUMPtec's DIMM-PC is 40 x 68 mm, unknown thickness, and includes a 486/66 with 16 MB, a 16MB flash drive, and various controllers. The wearable computer is served from one running Linux.

Alternatively there's NETsilicon's NET+ARM, but much of the value of that is in the RTOS which is probably not what we would want on cigartin.

IBM's "microdrive" hard disks are 340 MB in a CompactFlash Type II slot, 48.2 x 36.4 x 5 mm.

So a DIMM-PC and a Microdrive would fit in the tin (assuming the DIMM-PC is thin enough), then all we would need is the sockets: 5V in, a couple of UTPs for Ethernet, and a serial port. They will fit in the remaining space, no trouble, making a fully capable Linux or FreeBSD based firewall / router.

Incidentally, Richard, does your digital camera take CompactFlash Type I or Type II? I got the impression that it was about 3 mm thick, in which case that's Type I.

Nick B

Nick's followup

... including SMTP/POP3/DHCP/DNS/HTTP/FTP server. The CPU and memory on one of these DIMM-PCs is equivalent to

In other words, one of these is sufficient to be a complete small-company corporate network server.

A bunch of alternative configurations:

Nick B

David Jones: On wearables:

The contender above, which was up and running on 1/22/99, is only slightly higher and wider than a box of matches but is one third the thickness, measuring 2.7" by 1.7" by .25" for a volume of about a cubic inch, less than a tenth the size of the previous record holder. This record too will fall in due course, let's see how long it takes.

The inches convert as: 69 x 43 x 6 mm +- 1mm or so for the conversions from inches to mm.

Concerning heat dissipation the 2W that a DIMM-PC takes shouldn't be a problem, but a couple of ethernet transceivers will push that up quite a lot I would've thought. It might run quite warm.


David Jones again

It struck me that the PC-DIMM might score very highly in terms of computer power per unit volume.


What's the densest form of compute power? In terms of computer power per unit volume. SPECint95/cc.

Really the interest is in stock solutions. Using stock mounting, cabinets, power supplies, interconnect, and CPU boards, what's the largest amount of compute power I can fit into a cupboard (or whatever).

Is it just thousands of PC-DIMMs glued onto a ribbon cable or am I better off going for rack mounting SparcServers or something?


Nick's followup

I suspect a NETsilicon NET+ARM solution running Beowulf might do OK: that way you get the networking on-chip.

Someone in the Beowulf community is making lots of multi-ARM PCI boards, with ARM+memory on a daughterboard, and disk controller on another daughter board. I think it was 32 StrongARMs per PCI slot, but that might be a bogon.

Is it just thousands of PC-DIMMs glued onto a ribbon cable or am I better off going for rack mounting SparcServers or something?

In short, dunno, but I bet the Beowulf guys do.

Nick B

Nick's further followup

You know better than to ask such a question. Compute power measured how? BogoMIPS per light-year?

If you want pure SPECint95/cc, a single PC-DIMM with an IBM Microdrive would do OK, because SPECint95 doesn't scale too well to maspar systems. There's SPECint_rate95, I guess. Or TPC-D QphD/cc might be a better benchmark. But it really does depend.

Nick B

Nick on other hardware:

Phytec make something very similar to the DIMM-PC: a bit bigger but more expandable (e.g. two PC-MCIA slots). It has the same CPU, the AMD Elan SC400.

VersaLogic make something similar: a bit larger but with standard connectors.

Doubtless just about every embedded controller manufacturer has something along these lines. The Jumptec is the only one I've seen with an onboard filesystem.

The Beowulf ARM project is at

Nick B

Mark: Jumptec's Chipdisk

Jumptec's Chipdisk, A flash disk module, although only available to 48 Megs, is 31mm x 52.5mm.

It has low power consumption and has cache, defect re-mapping and standard IDE interface. Given that the DIMM-PC has 16Meg flash already, that's 64Meg with one Chipdisk, 112Meg with two.



I was wondering how best to get storage in there. If we want to use the IBM drives then we need a CFA interface. We could use a PCMCIA CFA card.

You say "88 x 83 x 8". No way; that's 7.5% overstated. Interior dimensions are 79x86x8. I measured the internal height by trimming an eraser to fit exactly.

BTW, The rounded corners remove 31 mm^2 of area or 248 mm^3 of volume, and must be taken into consideration when trying to fit components.

Nick B


See html/Fcfa.html for a card to adapt CFA into IDE. Probably overkill. Also contains some other links about putting Linux onto a CFA card.

indirectly from Tim Morley

Having mentioned cigartin to Tim, he pointed me thus:

Have a look at uClinux (at 68k based modules with ethernet and lcd driver that should be able to run linux) or MiniPleb aka Photon (strongarm on a cardcard sized thingy)


Mark on the wearables DIMM-PC serve r

The BBC have caught up with this in their news site. Notice that the wearables group are working on a pentium machine utilising the 340MB IBM microdrive.

Nick not really relevant to cigartin but: disk drive densities

Date: Fri, 19 Feb 1999 15:51:57

A quick table of the volumetric data densities of various (IBM) disk drives. Their newest notebook drives get nearly a megabit in every cubic millimetre of drive (that includes electronics, heads, enclosure, etc).

drive cap (GB) dim (mm) vol (mm^3) density (Kbit/mm^3)
travelstar 14GS 14.1 17x70x100 119,000 950
travelstar 10GT 10.0 12.5x70x100 87,500 915
deskstar 25GP 25.0 25.4x101.6x146 375,000 535
ultrastar 36XP 36.4 41x101.85x147 613,850 475
microdrive 0.34 5x36.4x42.8 7,790 350

Nick B

Mark pointing out that IBM's microdrive has won a technology award

the 340MB microdrive has won the Mobile Insights "Technology Achievement of the Year" award: IBM's press release.

Leon cigartin data storage

Hi Nick!

I'm very interested in your efforts to construct a micro-sized computer from scratch. I work as an assistent professor in the Information Storage Technology Group at the MESA+ research institute of the University of Twente, NL. I noticed on your website ( that storage seems to be a problem. The IBM microdrive is kind of big. What about this:

Dimensions :15x15x2 mm
Capacity : 20 GBit
Min. data rate : 300 Mbits/s
Max acces time : 2.5 ms
Power : 1 W
Standby power 1 mW

It doesn't exist yet, but it will certainly become available within 4-6 years from now. The principle behind the memory is that we have 10.000 or more mechanical probes in a 1x1 cm array mounted on top of a discrete magnetic medium. You might want to have a look at our website for more info. Follow the link Probe Recording on our research page:

Apart from the fact that I think you might be interested, I would also like to ask you and your mighty friends whether these specs are what you need. What is more important: storage capacity or a high data rate? What power consumption is acceptable? I know quite something about magnetic data-storage, but my knowledge of these small computers is limited. I bought a PalmPilot last year, but fear to open it up :).

I would be very interested in more details. Did you already start constructing such a cigartin system? If so I would love to buy it, it would make a great demo. We might also be able to help you in the construction.

I have the impression we could help each other. What do you think?


Leon Abelmann
Information Storage Technology Group
MESA Research Institute, University of Twente

Now at:
Data Storage Systems Center
Carnegie Mellon University
Roberts Hall 231
Pittsburgh PA 15213

tel/fax: +1 412 268 6610
fax: +1 412 268 8554 (Only use if above number does not work)
mobile: +1 724 713 1516

Richard Brooksby reports on the World's smallest web server (for now) - Mon, 1 Nov 1999 says: In the photo above is the webACE: a Fairchild ACE1101MT8 microcontroller programmed as a Web server and containing two tiny web pages in its on-chip memory. Since the ACE1101MT8 is the smallest available microcontroller, I believe that this is (at least for the moment) the World's Smallest Web Server.
Last updated by Fri 28th Jan 2000