MMC unit 0 (1024M)
0>PLUSIDEDOS          64K sys
0>General           4096K data
0>CPM-A              320K data
0>CPM-B              512K data
0>CPMStuff           512K data
0>Dev                256K data
0>Next               320K data
0>~~~~~~~~~~~~~~~~ 10304K FREE
24 free partition entries
MMC unit 5 (1024M)
5>1>NEXT            1008M FAT32

CAT ASN on the other hand, displays which partition or disk is assigned to which drive. The syntax is similar to CAT TAB:

CAT [#n] ASN

where, again, #n is an optional stream for the output to be redirected to. On a standard ZX Spectrum Next with a single SD reader and prepared CP/M (whose virtual drive a: as we have discussed would be already automounted), giving:

CAT ASN

would produce the following output:

A: ---Mounted FS---
C: 5>1>NEXT
M: 4>RAMdisk

If you are asking what happened to the IDEDOS partition we displayed earlier, it's not mounted because IDEDOS partitions do not auto-mount. To mount them (or any other partition or virtual/physical disk) you will need to employ the following commands:

MOVE ... IN, MOVE ... OUT and REMOUNT

In order to assign (mount) a disk/partition or virtual/physical disk to a drive you need MOVE ... IN. Its syntax is as follows:

MOVE drive IN mount_point

where drive is any valid NextZXOS drive (a: to p:) and mount_point is either a device>[partition][>][partition_name] or a filespec of a virtual disk. Devices that don't have partitions are written as X> where X is the device number, while devices that have partitions are written as X>Y>[partition_name] where Y is the partition number for FAT partitions and X>partition name for IDEDOS partitions. In the case of IDEDOS partitions the number can be totally omitted as well if on device 0. Assuming that we had unmounted the RAMdisk, in order to mount it again in some other drive, we'd need to do:

MOVE "o:" IN "4>"

Notice that there's no partition number following the 4> as the RAMdisk has no partitions. To mount a +3 disk image named mike.dsk located in c:/images/ into drive b: we would need to:

MOVE "b:" IN "c:/images/mike.dsk"

Whereas to mount an IDEDOS partition (for example one of the ones we examined earlier) you would have to:

MOVE "e:" IN "0>CPMSTUFF"

or