IsFileSystem

returns whether an AmigaDOS handler is a file system (V36)

Returns whether the device is a file system or not. A file system supports separate files storing information. It may also support subdirectories but is not required to. If the file system doesn't support this new packet, IsFileSystem() will use Lock(":",...) as an indicator.

name

Name of device in question, with trailing ':', e.g. "DF0:"

result

Flag to indicate if device is a file system

AmigaDOS uses message-passing between Processes in order to provide operations such as Open(), Close(), Write(), etc. These messages are called "packets". This message type is defined as the DosPacket structure (see <dos/dosextens.h>) which builds upon the exec Message structure (see <exec/ports.h).

The Processes which receive the DosPackets in order to, for example, make the Open() function work, are generally called "handlers", because they handle incoming command messages and return these messages (DosPackets) to the sender once the requested operation has been performed.

A "handler" is started either as part of the dos.library initialization when the operating system is started, or it may be mounted by a mass storage device driver, or through a mount file in "DEVS:DOSDrivers", for example. Each such handler has a unique device name, such as "PRT" or "DF0". Note that the AmigaDOS usage of the term "device" differs from the exec.library usage in that an AmigaDOS "device" is usually depending upon an exec.library device such as "trackdisk.device" to deliver its services.

The difference between a mere "handler" and a file system, as indicated by the value returned by IsFileSystem(), is that a file system provides access to named files and/or directories, typically in the form of a hierarchical file system layout. Put another way: a file system supports operations such as Rename(), Delete() and SetProtection() whereas a handler is typically limited to Open(), Read(), Write() and Close() operations.

Lock()