type field is specified, it must be preceded by a dot. Unlike some other BASICs, NextBASIC does not automatically allocate a type to files if one is not specified.

You may find it useful to add your own types – a popular convention is to use .BAS to identify NextBASIC file types and .BIN or .COD to identify machine code file types.

NextBASIC already understands a number of popular types. Going to c:/nextzxos with the browser, placing the cursor over browser.cfg and pressing ENTER will return the most commonly used ones together with the action that will be taken when the Browser launches them.

The characters * and ? are called wildcards and have a special meaning to NextZXOS. They're used to substitute ranges of characters or specific characters in filenames and folders. We'll see why this is particularly useful further below.

The dot character . also has a special meaning according to how many we use. If we use one (.) it means this folder and if we use two (..) it means the folder one level up. Keep this information in mind as it will prove very useful in the examples we'll encounter.

The following are some examples of valid filenames:

• z
• squares
• m:picture.bin
• a:fred
• 13a:hello
• 0M:CAPITALS
• file name
• test.bas
• philip
• glass.mus
• a:a.a
• c:/nextzxos/browser.cfg
• c:\nextzxos\browser.cfg
• 7:dubious

while the filenames below are illegal and attempting to use them will produce an error:

• <>-+=!& (must not contain any of these characters)
• *test (cannot contain an asterisk)
• te?st (cannot contain a question mark)

Note that in the list above we've made two assumptions regarding valid filenames, and these are that drive names a: and m: are virtual disks and the RAMdisk respectively. User areas are acceptable parts of filenames ONLY if the drive's filesystem allows them; otherwise you will get an error.

With that information in hand, let's start examining below the main commands for working with files.

LOAD

LOAD as its name implies retrieves a file from a drive and puts it (loads it) in the computer's memory. Depending on how it was saved (in the case of NextBASIC programs) or named (in the case of machine code software) it may also execute it as well. It takes the form:

LOAD filespec [MODIFIER [options]]

where filespec is a filename as described in the previous section followed by an optional MODIFIER directive (SCREEN$, LAYER, CODE, DATA, INT, INPUT or BANK) which in turn may have optional parameters.