Hi, Rich. On Sat, Jan 24, 2015 at 12:58:48PM -0500, Rich Freeman wrote: > On Sat, Jan 24, 2015 at 12:27 PM, Alan Mackenzie <a...@muc.de> wrote:
> > On Sat, Jan 24, 2015 at 11:37:00AM -0500, Rich Freeman wrote: > >> Do you regularly update the software on your embedded system? > >> systemd-183 hasn't changed a bit since the day it was released. > > systemd-183's velocity is unchanged from the day it was released, and > > it isn't slow. > You'll have to define what you mean by velocity here, not that it > really matters since we can quibble over definitions all day long. > systemd-183 today is identical to systemd-183 the day it was released. > It is a snapshot in time. When you take a photograph (a snapshot) of a fast moving thing, the photo may give the false appearance of the thing being stationary, whereas it is in reality a fast moving object. That is my feeling about systemd. But I agree, the point is not worth quibbling over. > >> The fast-moving target bit is only an issue if you want to keep > >> updating it. > > Quite the contrary - the fast-moving bit is an issue if you _can't_ > > update it, or if updating is expensive, which is frequently the case > > for embedded systems. Fast-moving software is likelier to be buggy > > than well established traditional software. > You do test your embedded devices before you release them, right? Absolutely. They are tested most searchingly, both by us and by the customer. However software not written by us is assumed to be fully tested by its suppliers, hence is only tested by us at the "System Integration" level. Generally, that's a safe assumption when speaking about proprietary embedded OSs. Clearly, SW which incorporates GPL bits must itself be GPL, and I have no experience of working on any such embedded SW. > >> That said, systemd doesn't change THAT much between versions as far as > >> the key interfaces go. > > But busybox changes even less. > It is also used far less. Are you sure? I had the impression that busybox was very widely used on embedded devices, such as routers, which are made in very large numbers. > Do you really think that you're less likely to have problems with > busybox mdev and busybox init than with whatever version of backported > version of systemd RHEL is using six months after release? Yes, I do, certainly on an embedded system. Even on a desktop, mdev works well. I've used it. The only reason I gave up on it was because a package I use (I can't remember which one any more) suddenly acquired a hard dependency on udev. :-( > -- > Rich -- Alan Mackenzie (Nuremberg, Germany).
