Re: Elks Distribution

[Neil Holmes <neil.holmes@zoom.co.uk>]

I will, indeed, look very closely at your remarks as I move forward. I
am particularly interested by the partition.c.

I'll keep everyone posted.

Many Thanks

Neil

On Sat, 2002-05-25 at 23:55, Riley Williams wrote:
> Hi Neil.
> 
> > It sounds like your distribution is in advance of that which I have
> > produced thus far Richard.
> >
> > My first "stable" version is ready now. I am not sure what the
> > procedure is here but I have attached a zip file EDE.zip to this
> > email which contains two floppy image files for install disk one
> > and disk two.
> >
> > I would be interested to hear how it runs elsewhere. 
> >
> > Here are some notes on what to expect.
> >
> > - I have tested it on 80286 and 80386 machines.
> > - I recommend creating a dos partition before starting (at least 20Mb)
> > - The install will create a 20Mb ELks /dev/bda1
> > - This first version will only install to /dev/bda1
> >
> > DON'T TRY IT UNLESS YOU HAVE A BLANK SYSTEM TO PLAY WITH
> 
> Some thoughts regarding the above which you may wish to consider:
> 
>  1. If the target partition has to be fixed, then it would make more
>     sense to select /dev/bda4 as the ELKS partition to use, as MSDOS
>     (and most other operating systems) allocate starting at the low
>     end of the numbers.
> 
>  2. The ideal would be to have it parse the partition table looking
>     for a suitable partition, where "suitable" is defined as being
> 
>      a. Smaller than 31M (the claimed limit of the file system
> 	format used for ELKS, and
> 
>      b. Of partition type 80 hex (the "Old Minix" partition that ELKS
> 	uses for its filesystem).
> 
> I've added a command to the elkscmd CVS tree that deals with point 2b
> above (look for partype.c in the disk_utils directory) and the source
> is enclosed for reference. It takes the desired partition code as a
> command-line parameter, so is generic in that sense. It also checks both
> /dev/hda and /dev/sda if it can't find /dev/bda so in that sense is not
> ELKS-specific either.
> 
> Best wishes from Riley.
> ----
> 

> /* partype v1.0.0 Partition type locator
>  * Copyright (C) 2002, Riley H Williams G7GOD,
>  * Released under the GNU General Public Licence, version 2 only.
>  *
>  * This program searches the partition table of the primary hard drive for
>  * a partition with a particular hex code for the partition type. It only
>  * searches the four primary partitions, not logical partitions.
>  *
>  * If it finds any partitions of the specified type, it displays the name
>  * of the lowest numbered partition on stdout.
>  *
>  * On completion, it returns one of the following error codes:
>  *
>  *	  0	No partition with the specified type was found.
>  *
>  *	  1	Partition /dev/bda1 has the specified type.
>  *	  2	Partition /dev/bda2 has the specified type.
>  *	  3	Partition /dev/bda3 has the specified type.
>  *	  4	Partition /dev/bda4 has the specified type.
>  *
>  *	 65	Partition /dev/hda1 has the specified type.
>  *	 66	Partition /dev/hda2 has the specified type.
>  *	 67	Partition /dev/hda3 has the specified type.
>  *	 68	Partition /dev/hda4 has the specified type.
>  *
>  *	129	Partition /dev/sda1 has the specified type.
>  *	130	Partition /dev/sda2 has the specified type.
>  *	131	Partition /dev/sda3 has the specified type.
>  *	132	Partition /dev/sda4 has the specified type.
>  *
>  *	252	The raw drive is not seekable.
>  *	253	Neither /dev/hda nor /dev/bda is available.
>  *	254	An invalid partition type was specified.
>  *	255	Usage message displayed.
>  *
>  * Note that the error code only indicates the FIRST partition in the
>  * sequence listed above that is of the relevant type.
>  */
> 
> #include <stdio.h>
> 
> unsigned char digit(char ch)
> {
>     if (ch >= '0' && ch <= '9')
> 	return ch - '0';
>     else if (ch >= 'A' && ch <= 'F')
> 	return ch + 10 - 'A';
>     else if (ch >= 'a' && ch <= 'f')
> 	return ch + 10 - 'a';
>     else
> 	return 0;
> }
> 
> int main(int argc,char **argv)
> {
>     unsigned char table[64];
>     FILE *fp;
>     char *ptr = argv[1], *drive = "/dev/bda";
>     unsigned char n, partition = 0, result = 0;
> 
>     if (argc != 2) {
> 	fprintf(stderr, "Usage: %s <type>\n\n", *argv);
> 	fprintf(stderr, "Where <type> is the hexadecimal partition type required\n");
> 	exit(255);
>     }
>     while (*ptr) {
> 	partition *= 16;
> 	partition += digit(*ptr++);
>     }
>     if (!partition) {
> 	fprintf(stderr, "ERROR 1: Invalid partition type: %02X (%s)\n",
> 		partition, argv[1]);
> 	exit(254);
>     }
>     
>     if ((fp = fopen(drive,"rb")) == NULL) {
> 	drive[5] = 'h';
> 	if ((fp = fopen(drive,"rb")) == NULL) {
> 	    drive[5] = 's';
> 	    if ((fp = fopen(drive,"rb")) == NULL) {
> 		fprintf(stderr, "ERROR 2: Can't open raw drive.\n");
> 		fprintf(stderr, "         Searched /dev/hda - /dev/sda - /dev/bda only.\n");
> 		exit(253);
> 	    }
> 	}
>     }
>     if (fseek(fp,0x1c0,SEEK_SET)) {
> 	fprintf(stderr, "ERROR 3: Can't seek to partition table in /dev/bda\n");
> 	exit(252);
>     }
>     for (n=0; n<64; n++)
> 	table[n] = fgetc(fp);
>     for (n=4; n; n--)
> 	if (table[16*n-14] == partition)
> 	    result = n;
>     if (result) {
> 	printf("%s%d\n",drive,result);
> 	switch (drive[5]) {
> 	    case 's':
> 		result += 64;
> 	    case 'h':
> 		result += 64;
> 	    case 'b':
> 		break;
> 	}
>     }
>     exit(result);
> }