On (06 Jul 94) Rod Speed wrote to Keith Richardson...



 RS> Because all it does is rewrite the loader which is used to load the

 RS> first bit of DOS proper off the bootable drive. Its just a small

 RS> piece of code and so its completely safe to rewrite that small

 RS> piece of code. The FDISK /MBR doesnt touch the partition table or

 RS> the BIOS parameter block.



 KR> partly true, since it is impossible to write less than 1 sector on

 KR> a disk (at least all the ones that i have ever come across,

 KR> although you no doubt know of an exception) the partition table,

 KR> although it is not altered, must be read from the disk and

 KR> re-written to it.



 RS> Well, thats just pedantic nit picking.



 KR> hahahahahahahahahaha

 KR> hahahahahahahahahaha



               ......etc.....etc.....



 KR> hohohohohohohohohoho

 KR> oho    



 RS> Pathetic really. I've seen little kids with a less transparent

 RS> debating technique.



 debating technique? 

i was expressing a normal restrained level of amusement at you

complaining at pedantic nit picking, maybe i will have to include a

[debate mode on/off] indicator in future to prevent you from getting too

confused.



 KR> i gotta give it to you rod, you've got a wacky sense of humour.



 RS> We'll see.



oh maybe it is me that is confused, and you are really serious when you

say those funny things.



 RS> Sure, the only way to rewrite the MBR in a strict sense is to read

 RS> in the whole sector, replace the bytes which make up the MBR, then

 RS> rewrite the whole sector again. But in a practical sense you have

 RS> just rewritten the MBR even tho in a strict sense you have

 RS> rewritten the whole sector.



 KR> no, in a strict sense you have just updated the mbr, but in a

 KR> practical sense you have read, and rewritten the entire boot

 KR> sector.



 RS> Thats supposed to be news ? I already said that.



as i read it, you said the opposite to me, the stricts and practicals

are interchanged, but then that is probably pedantic nit picking.



 KR> i have had to recover systems where power failure etc happened at

 KR> exactly the wrong moment.



 RS> So fucking what in the context of what was being discussed at the

 RS> top ? What choice have you got when you already know that the data

 RS> in the first physical sector is not correct, you have to rewrite

 RS> the first physical sector anyway.



 PE> How come you made it sound like "fdisk /mbr" was an innocuous

 PE> command?



in the context of that. i think that, had paul had realised what was

actually being done, he would have done what i would also have done, and

backed up the boot sector before doing the fdisk /mbr.



 KR> the truely paraniod would keep a copy of the boot sector on floppy

 KR> just in case.



 RS> True. And that can be worth having, but not for this microscopic

 RS> risk of a power failure at the time of the FDISK /MBR command, but

 RS> to allow graceful recovery when anything damages the first physical

 RS> sector on the drive. Particularly if its part of a disaster backup

 RS> which also keeps the other stuff like the cmos contents and stuff

 RS> too.



the most probable cause of losing your boot sector would be a bad write,

so the less times that you write it, the less risk of losing it.

personally, i wouldn't bother with the cmos contents, as, on most ami

bios machines, a runnable system can be regained with just a couple of

keystrokes, not so with the boot sector.



 KR> i do not like boot manager's habit of diddling with the boot sector

 KR> every time you load dos either.



 RS> Well, you are perfectly welcome to like or dislike whatever you

 RS> like like that. IMO its just being grossly anal retentive to no

 RS> real useful benefit. And if you want to be so paranoid the fix is

 RS> trivial, keep a copy or five of it on floppys.



well at least us anal retentives are ecologically sound, we dont go

spreading shit all over the countryside like others and their dogs.



 RS> Still got absolutely nothing useful at all to say about what we

 RS> were actually discussing, just what an FDISK /MBR actually does in

 RS> the first physical sector.



just taking issue with your "perfectly safe" comment. you make it sound

as if nothing can go wrong, it can, and occasionally does.



                            keith





... Kill them all!  .... Let God sort them out.



--- PPoint 1.80


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