Subject: Re: Hard Drive standard file structure... On <27 Oct 94 13:46> [EMAIL PROTECTED] wrote:
Hi Simon! (and everone else) Si> The time has come to work out the Si> standard file structure for this new Si> hard-drive thingummybob... The ONLY thing I'd like to see on ALL the various file-systems is the facility to Partition a BIG HD so we can run the several different types of file system on the same HD, eg. CP/M defines in it,s DPB a reserved number of tracks as a 16bit value so it can be placed virtually anywhere on a large HD and take up as much space as defined in the dsm field... Any unix style system should also be made to do this as well IMHO:-) I've mentioned this elsewhere before... a small unix style pd filesystem is available in C source form inside the UZI package on oak.oakland.edu It doesn't use 32bit values just 16bit for speed and ease of z80 implementation so each mounted logical drive is restricted to 32Meg in size. With some extensive editing it'll probably even compile under small-C v2! though I think the resultant assembler source would need extensive hand-optimisation as Small-C is not a very clever code generator;-) Si> I'm going to see about posting this to Si> the SAM Users mail thingy as well, Si> and I'll see if I can post all input from that here too... Si> Basically, how should we arrange it all? Si> I'd like a filesystem that has no Si> limits on no' of files, allows user Si> status (ie password protected areas, Si> file groups, etc.... to allow Si> networking / fileserver activity if it ever happens)... I think UZI system should do that... Password protection with xor scrambling of data based on the key should be just a *simple* extension. simple meaning if you can write a filesystem from the ground up this feature should be easy;-) Si> Basically, we've got to define how Si> we're going to store the files on the Si> disc, how it finds them when they're Si> stored there, and what's held in the Si> directory structure. Si> Any ideas anyone? As we're dealing with a fixed drive we can theoretically do what ever we like as it doesn't need to be compatable with ANY other platforms physical format.. So just use the good features of the various systems, make the nesesary comporimises needed to allow acceptable performance on a z80 machine ie if 32bit values slow it down use 16bit pointers and partition large HD's it smaller logical units, after all who needs to process more than 32Meg items on a z80? Si> I'm currently thinking of 64 chars per Si> directory entry, allowing 20 Si> character (or so) filenames, with Si> possibly a quick-to-access file system Si> (ie one that is a combination of FAT and Si> sector/head/track at the end of each Si> logical sector (ala SAM)). 510byte sectors again Si!?! Makes for crappy random-access file performance! ProDos random access is much better than master-dos, not that I'd suggest doing a CP/M style directory structure... I've noticed on this pc1512 running pcrr1.60a olr that it is damned sloooow at random-reading the prior message don't know if that's an MS-DOS problem or somthing to do with the MS-DOS TP runtime package... Plus 510 byte isn't binary maths friendly but 512 is, obviously;-) regards Johnathan. ___ Olms 1.60 [Evaluation] -- |Fidonet: Johnathan Taylor 2:2501/307 |Internet: [EMAIL PROTECTED] | | Standard disclaimer: The views of this user are strictly his own.
