Putting Linux on a server or workstation is easy. There's plenty of RAM and disk space and most distributions are relatively compatible. Embedded Linux is more difficult to set up, and migration between embedded Linux implementations tends to be just slightly less painful than moving between incompatible operating systems.
Will the differences between the basics of an embedded Linux be close to another? Yes, but not right now. The Linux Standards Base (LSB, www.linuxbase.org) is well past version 1 and seems to have garnered support from all major Linux supporters. Although this is a good start for embedded Linux standards, embedded applications tend to be more demanding than conventional workstation or server applications.
Look for embedded standards at the Embedded Linux Consortium (ELC, www.embedded-linux.org). It has support from most of the embedded Linux community and uses standards like LSB and POSIX as its basis. Unfortunately, an ELC embedded standard isn't expected until the end of 2002, and compliance suites are targeted for 2003. The Strawman (beta) version is in the works, but only ELC members have access to it at this time.
It will be interesting to see the effect that the final release has on the embedded market. Although the initial LSB release had some fanfare, the ELC release may be more muted. Hopefully, things will actually be more celebrated because it's something that embedded developers need to know about. Likewise, the release had better be something worth waiting for. Otherwise, it will not likely have the effect of the desired convergence.
Even if the ELC's efforts aren't fruitful, embedded Linux implementations will still be much more compatible with each other than with any other embedded operating-system line. If there's good fruit, Linux will definitely continue to make inroads compared to the embedded operating-system competition.