We are using something similar to PC/104 but a non standard form factor with no PC/104 bus, for function specific applications. i.e. we have inexpensive low powered devices with have PC specs, but small form factor (10cmx10cm) running SoC's. We also have scan tunnels running Linux on fan less boxes, that are of PC' spec with Pentium M and Core processors. This is what I was refereeing to as semi-embedded. The software running on the systems are single function. The device is embedded in a larger device collection (i.e. scanners, dimensioners etc) on a tunnel frame. In this industry the long term availability of parts are important as the whole system has to be serviceable and the software don't change unless there are pertinent bug fixes or security issues. We boot from USB keys on those systems to image the flash, and I can tell you for sure that we are getting new systems installed as we speak, that doesn't support boot from non-modified USP keys. Trying to push a 900mb image (silly,yes I know but these are vendor supplied images) over a serial port would simply be a exercise in frustration on a few hundred systems. This is where a USB boot come very handy.
Also, on our own devices where we have smaller images (4M to 35M), USB boot is still very convenient for testing while developing your flash image as we can simply pull the key, insert it into a laptop, edit some files and try again. In both senarious USB based boots are only temporary and not for production systems. But yes, these aren't real embedded projects, but rather simply small formfactor PC's. But either way the boot issues are there, and it's not un-common. However reformating the USB stick is easy and quick so I don't see why this is an issue, so stop pretending that it's strickly a leagacy problem and embrase the working solution. On 3/7/07, MobileLinux <[EMAIL PROTECTED]> wrote:
> Noone claimed they boot the system from USB. Then BIOS is irrelevant.... > the thread drifted when some people just wanted to point out that > for your mobile use-case scenario non HD-USB booting BIOS might > be an issue. ...then BIOS is relevant. The originator of this thread asked for USB, so he presumably knows how BIOS issues pertain to PC rescue, and yet still wants USB functionality. If you want to argue about more general use cases like ours.... ...then measure importance and form an opinion. Only 3-6 major PC BIOS vendors exist, all of whom have supported USB-HD for 6 years, and USB-ZIP longer. Our opinion: legacy issues on old machines fall into a less-than-worrisome slot. The workaround is a grub boot floppy or kexec/kboot. As time marches on, legacy issues become even less a problem, while USB device capacity grows and cost shrinks. > In any case it appears to work just fine for you so all's fine - yours, The fallacy implied is that we are exceptional. What I could retort is, "too bad it doesn't work for you, since it works for everyone else." :-)) P.S. Embedded devices and field service do not work as you described. No nexus really exists between USB and embedded devices. The subject is worth a few lines to clear up confusion. For decades now (prior to JTAG, and still today) embedded systems have used serial ports. They are not always visible as DB-9 connectors on the box, but the circuitry exists. Connection can be a bare header on the embedded board. Only if the customer/device must perform serial comm is there a DB-9 port on the case. Field service involves cracking the case, plugging into the serial comm header, and flashing an upgrade. If a DB-9 port exists then that is used instead. Either way, this operation is rare, not a regular occurrence, so speed is unimportant. What matters is part count and design simplicity. USB is massively huge overkill for flash upgrades. Any company you find desiring that functionality is going broke soon. Flash is the most common boot method, not "internal storage USB-CD/stick booting" whatever is meant by that phrase. Boot flash is just memory mapped. It has nothing to do with USB. The reason flash became so popular for embedded systems is that upgrades can be performed without part exchange. The idea that companies now want to use USB flash sticks is backwards. More likely would be an EPROM. These are traditional in embedded systems. They pop straight out of their sockets, as opposed to soldered flash, which requires electronic communication to change. EPROMs are programmed with specialized EPROM programmers, as you may know. The upgrade method is to swap chips mechanically. No USB here. Recent years have seen embedded devices with network functionality using web-browser interfaces for flash upgrades. Those are your Linksys and D-Link boxes. That's Ethernet from a PC, not USB. Since they already handle Ethernet, it costs nothing extra to implement flash u/g over Ethernet. No USB here, either. PC/104 is a normal PC. Flashing the BIOS happens exactly like a normal PC. Typically you plug into the serial port, or run "flash.exe" from a boot floppy (plugging into the floppy port a spare floppy drive). Again, not USB at all. Unless you're developing a USB device, it won't enter the picture. If you are, there are dozens of vendors for USB stacks, chips, etc. But you're still not going to boot the device from USB, it will boot from memory-mapped flash ROM. The idea that USB is somehow causing embedded systems headaches is high weirdness! ----------------------------------------------------------- If you wish to unsubscribe from this mailing, send mail to [EMAIL PROTECTED] with a subject of: unsubscribe t2
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