| 
GEOS SDK TechDocs
| 
| 
The File System
| 
2 File System Overview
The GEOS file system was designed to meet two goals. First, the file system should insulate geodes from differences in hardware, making them device independent; and second, it should give geodes all the functionality they might plausibly want without being cumbersome.
One of the hallmarks of GEOS is its ability to insulate applications from differences in hardware. The GEOS file system plays a large role in this. Geodes which need access to files make their requests to the GEOS file system, which accesses the actual storage media. The virtues of this approach are several:
-
Geodes can rely on a consistent API for accessing media. When an application needs to open a file, it uses exactly the same techniques whether the file resides on a hard or floppy disk, a network drive, or some other medium.
-
GEOS can easily expand to make use of new technologies. To support a new storage medium, GEOS just needs a new device driver; all existing application binaries will automatically work with the new device.
-
Applications need not worry about what DOS the system might be running under. The GEOS file system does all interaction with the DOS and automatically takes advantages of each DOS' strengths. To support new versions of DOS, GEOS just needs new drivers.
GEOS is also flexible. Flexibility means more than just being able to use new technology in the same old ways; it means providing functionality to serve unforeseen purposes. GEOS provides this:
-
The file system allows such advanced functionality as virtual paths and directories. Files can thus be distributed across various media (for example, templates and fonts on CD-ROM drives, company files on a network drive, other documents on local hard disks) transparently to both user and application.
-
Other functionality can be added. For example, all GEOS files can have names up to 32 characters long, regardless of strictures on individual media. The file system maps the GEOS "virtual names" to device-dependent "native names" transparently to the user and application.
While GEOS provides this advanced functionality, it still lets geodes access the raw files. If a geode wants to access any file as a sequence of bytes (the DOS model), it may do so. Similarly, geodes may work with physical DOS directories if they wish to.
| GEOS SDK TechDocs
|
| The File System
| 2 File System Overview