Question: I can add/commit any file/folder to repo but index.php . When I add/commit index.php to any folder under my repo it gives error as below:

```
Command  Commit
Adding   D:\svn\projects\myrepo\index.php
Error    Commit failed (details follow):
Error    Repository moved permanently to
Error    'http://mydomain.com/repos/myrepo/!svn/wrk/RANDOM-HASH/';
Error    please relocate
Error    Repository moved permanently to 'http://mydomain.com/repos/myrepo/'; please relocate
Finished!

```

Repo: under : /var/www/svn/myrepo
url : <http://mydomain.com/repos/myrepo>
svm mod\_dav\_svn on Red hat linux with plesk
committing/adding through windows tortoisesvn

I could not find any clue why is it. I have same configrations on my local centos test server for svn and i can commit anything there including index.php.

What can be possible reason?

Answer: 
There are 3 reasons I can think of that a particular value could be used for the powerup IP:

1. convention - other processors in the same family/brand use the same location, and they want to give their customers a sense of familiarity
2. compatibility
3. certain areas are restricted or enhanced for certain purposes. The [6502](http://en.wikipedia.org/wiki/6502) for example has special faster instructions for accessing the first 256 bytes of memory from 0x00 to 0xff. On that CPU it makes sense to have the CPU start somewhere else. (I don't think the 8086 treats any area of memory specially however.)

compatibility and convention issues aside, the value that the instruction pointer gets when the processor powers up is largely arbitrary. For most models, the IP is intially either very close to the top of its address space (with enough room for a far JMP call to get it to where the real init code is) or at the very bottom (ie 0).

The [wikipedia](http://en.wikipedia.org/wiki/8085) [articles](http://en.wikipedia.org/wiki/Intel_8086) state that the 8086 was designed so that assembly source code from previous processors was easily *converted* to work with the 8086, but that's all. Apart from that there was no attempt to make it compatible with previous models.
1)In 8085 , upon reset the value of pc is 0000h. Therefore the wake up program should be written at 0000h location and can't be kept empty.

2) In 8086, reset values of CS & lP are FFFFH & 0000h resp. So 20 bit physical address will be FFFF0+0000=FFFF0H. It shouldn't be kept empty. Wake up program(code) is always in ROM and there for the ROM should be interfaced at last to cover FFFF0H.