*.??a Any filename with any type that ends in the letter a
a*.??? Any filename starting with a with any type
??a.?b? Any three letter filename ending with the letter a with a type having a b as second letter (for example dba.dbf)

While these won't:

*d.* * not the last character in the Name field
*.scr.* * not the last character in the Name field
*.*d * not the last character in the Type field

As it's apparent from the examples above, combinations of very few characters can represent a wide array of filenames which is exactly why wildcards are invaluable in managing our files.

Filesystems

We've also talked about filesystems; more specifically about FAT and IDEDOS/+3DOS but not specifically about what these represent. In a few words, a filesystem is a specific way of organising information that's located on a storage medium. There are filesystems that are medium–specific (for example even though it doesn't have a specific name, the way files are stored onto tape is a filesystem in itself) and filesystems geared toward general use. NextZXOS supports 3 (or rather 4) filesystems: the ZX Spectrum native tape filesystem, +3DOS (that comes from the ZX Spectrum +3¹³ principally geared towards floppy disks), and two variants of the FAT filesystem, FAT16 and FAT32 (their main difference where NextZXOS is concerned is capacity). FAT is the de-facto standard filesystem for most modern removable media (like the SD cards the ZX Spectrum Next uses). Each filesystem has its pros and cons which affects slightly the way NextZXOS operates. As we've already noted earlier not all features are available on every supported filesystem; this obviously affects some of the features we'll examine below.

IDEDOS (which comes from the +3e) is not a filesystem in itself but a scheme that allows multiple +3DOS "partitions" to occupy a single physical disk, in order to facilitate the use of large media like hard disks.

Partitions

In the introductory notes and the Filenames section, we've mentioned the term partitions either by themselves or in conjunction with one of the filesystems mentioned above e.g. a FAT partition. This is a bit misleading and in reality it's an acceptable mashing of two terms: XXX filesystem type AND partition – a partition formatted with the XXX filesystem. In other words a FAT partition is a partition formatted with the FAT filesystem (could be either FAT16 or FAT32 – using FAT as a portmanteau term is acceptable use).

But what is a partition? Nothing more than an arbitrary slicing of available space on a storage medium, usually to make it more manageable. An SD card for example could have one or more partitions and not all of the same filesystem. Note here that NextZXOS will always start from the first FAT partition on the first SD card on the system. If you remember the initial discussion, drives can be assigned to partitions; this process of assigning a partition to a drive is called mounting and we will examine it right after we briefly examine storage devices.

Storage devices and disks

For NextZXOS a storage device can be physical or virtual. We use the term disk for both but the former refers to an actual, tangible piece of hardware like the SD Card reader your ZX Spectrum Next is equipped with, while the latter is nothing but a file containing the image of a filesystem. NextZXOS uses a common set of controls to address and access both types of disks. Physical disks are generally –with the exception of tape– assigned a number per device (ie. the primary SD card reader and secondary SD card reader have differ-

¹³ The +3DOS filesystem is identical to the CP/M one.