Interesting article on the "costs of supporting legacy hardware"

[D. Hugh Redelmeier]

| From: Christopher Browne <cbbrowne-Re5JQEeQqe8AvxtiuMwx3w at public.gmane.org>

| I think that the thesis presented explains a lot about why mobile
| platform projects have a hard time staying viable.  You likely can't
| buy a cell phone from 6 years ago, and it would likely have *so*
| vastly less capacity than new hardware that few will be terribly
| interested in working on having modern software accommodate the
| elderly hardware.

Cell phone hardware is always the minimum to run todays software.
When you buy one, you cannot upsize it (and DIMMs and hard drives,
choose a better video card) nor can you do so later.  There is a real
force pushing towards minimal hardware: trying to keep the power
budget, the size, and the weight to the minimum, and of course the
price.

On top of that, the marketing system provides no incentive for
vendors to provide upgrades.

| And it seems to me that the "costs of supporting legacy hardware" has
| a fair bit of explanatory power for how difficult it is to support
| anything other than the very most popular OS.

Legacy is only one dimension of diversity.  There really is a lot of
other kinds of diversity.  Your SCSI card is a perfect example.

In fact, the opposite of legacy is also a problem: new hardware comes
out faster than support can flow from the kernel to the distros to the
releases.  As you point out, Hurd and Plan/9 would probably be
livelocked if they tried to support new hardware when it comes out.

| Linux (the kernel) has so many developers surrounding it that the
| community can support a pretty broad set of hardware.

Not broad enough.  Mostly due to trade secrecy.  And not quickly
enough.

The world that seems to be the "growing tip" of hardware is quite
closed to us.  Tablets and mobile phones have completely closed
"peripherals".

| The BSDs have fewer developers, but still have enough that they can
| keep up by "cherry picking" from what Linux gets supported.

I didn't think that they are copying code from Linux drivers.  I
assume that they gain information about hardware from code in Linux
drivers.

| I'm not quite sure how Plan 9 persisted to not be an inoperable
| curiosity; it suffered from the "only supports hardware that's only
| barely available" for quite a while.

I don't know.  But I remember when UNIX and Linux on PCs required you
to build your own machine out of carefully selected parts.  And
sometimes you'd be bushwhacked by hardware that changed without a name
change.

|  The hardware compatibility list
| (<http://www.plan9.bell-labs.com/wiki/plan9/Supported_PC_hardware/index.html>)
| is fairly large; the last time I attempted an install I ran afoul of
| the "oops, it doesn't support my SCSI controller" problem.

The correct solution was to buy a different SCSI controller.  Or give
up (which you and I did).

I suspect now most plan9 die hards (AKA users) run on virtual
hardware.  But I don't know.

| Entertainingly, the list of supported SCSI controllers hasn't changed
| much since then.

Isn't SCSI legacy now?  I mean the physical layer.  The only SCSI
hardware that gets used in my world is old scanners with unique
capabilities (35mm film scanner; flatbed scanner that handles legal
size paper).
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