### Working With Hard Drives

The Hard Drive menu can attach up to 4 drives. There are only unformatted hard drive images built-in so you will have to either supply your own or go through the process of formatting and otherwise setting up the emulated hard drive for use under your choice of emulated operating system.

Selecting Hard Drive → :slot → << unformatted hdv >> (or "emu" or "DREM") will connect an unformatted hard drive image to the selected controller slot. It will immediately prompt for a file to save the hard drive data. This is unlike the diskettes which will track changes internally and only ask to save when they are ejected.

On the command line use `-h :hdv` (or `:emu` or `:drem`) to attach a blank hard drive image and `-hx` to disable the hard drive controller.

The "drem" format is compatible with the DREM hard drive emulator available at https://www.drem.info/. It stores hard drive images as a pair of files. A `file.cfg` which gives the geometry and other information and a `file.dsk` which holds the data for all the blocks.

The "emu" format is compatible with the Gesswein MFM emulator available at https://www.pdp8online.com/mfm/mfm.shtml. Both the "drem" and "emu" formats allow for convenient copying of hard drive images to or from real TRS-80's.

FreHD emulation is not generally compatible with the Model II hard drive. Model II operating systems like the built in TRSDOS-2.0a which are unaware of the hard drive can import and export files using the FreHD utilities. But TRSDOS-II will fail to boot with `-frehd` enabled.