Boy, I am out of it. Memory failure, or not keeping up I remember when there was an absolute limit of 7 usable partitions on a disk. I forgot or never realized this limit went away for a DOS-formatted disk (I know Solaris and other basically different disk formats had different limits). Going back to MSDOS 5.0. The primary partition table 64 bytes, per AI) had 4 entries, but one of those could point to an "extended" partition with its own partition table, also of 4 entries (and 64 bytes), so the other 3 primary, and 4 extended partitions were all I could use for my data. If I tried to create one more extended partition, the format program refused. Some thing(s) could ONLY be in a primary partition (certain operating systems? multi-boot loader? I don't remember). Apparently, now there can be many extended partition tables, thus a practically unlimited number of partitions. 1. When did that change? Meaning with what level of Microsoft software, and what level of Linux, if Linux had also been limited to 3+4 originally? 2. I presume some old operating systems only recognize the first 4 extended partitions? Or can they totally not recognize a disk with a "new" DOS format mbr at all? This could be as a data disk if I am transferring data from a legacy computer to a current one. 3. Where are the groups of 4 extended partition definitions located? All in the first sector of the extended partition? Somewhere else? 4. If the extended partition tables are all in the first block of the extended partition, for a 512 byte sector size, wouldn't that mean a limit of 8 x 4 extended partitions? Hmmm, 32 is starting to jigle some memory cells as a possible limit for extended paritions. (nb the AI queries seemed to deny there was ever a limit on the number of extended partitions, probably because it wasn't trained on information that old) Carey