WHDLoad

WHDLoad is a software package for the Amiga platform to make installation of software to a hard disk easier, for such things as demos or games. Allowing for better compatibility for Amiga software, which can sometimes have hardware incompatibilities making them hard to use in emulated environments due to the widely varying hardware specifications of the Amiga product line across its history. WHDLoad basically circumvents the operating system in the Amiga for greater compatibility and preserves the original program environment.

WHDLoad makes it possible to autostart an installed floppy disk image by clicking an icon.

Two special parts are required, each one especially written for the client program: To install media, it must be read from the original disk and written to an image file on the hard drive by the "Imager". Then the installed program can be run from a virtual disk drive with the "Slave" interface.

The "Slave" interface allows interaction between the program and WHDLoad, and co-ordinates the reading and writing of files. This makes it possible to run or emulate programs that are traditionally incompatible with common emulators such as WinFellow, or WinUAE. WHDLoad can be easier to use than trying to figure out the exact configuration for the aforementioned emulators as well.

The primary reason for this loader is that a large number of computer games for the Amiga don't properly interact with the AmigaOS operating system, but instead run directly on the Amiga hardware, making assumptions about specific control registers, memory locations, etc. The hardware of newer Amiga models had been greatly revised, causing these assumptions to break when trying to run the same games on newer hardware, and vice versa with newer games on older hardware. WHDLoad provides a way to install such games on an AmigaOS-compatible hard drive and run on newer hardware. An added benefit is the avoidance of loading times and disk swaps, because everything the game needs is stored on the hard drive. Furthermore, floppy disks deteriorate faster than hard drives, so installing games with WHDLoad helps preserve the games further.

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Wikipedia