borghoff.jpg Notes from Borghoff et al. Emulation has some notable advantages over migration, not least that it guarantees the greatest possible authenticity. The document’s original bitstream will always remain unchanged. All (!) we have to do is make sure that a working copy of the original app is available. As it’s impossible to keep the hardware running, we have to emulate the original system on new systems.

In theory there are no limitations on the format of the record- even dynamic behaviour should be preserved ok. But there are three massive worries with emulation: (a) can it be achieved at reasonable cost?, (b) is it possible to resolve all the copyright and legal issues involved in running software programs over decades? and (c) will the human-computer interface of the long term future be able to cope with the mouse-and-keyboard interface of today’s applications? The only realistic way to answer (c) would be to create a “vernacular copy” (p.78) but this strikes me as migration under a different name – just my own thought.

Emulation is very well understood by IT techies. Software is regularly ported from one system to the next, to keep software companies in business. Makers of hardware often emulate the proposed chips and systems on current architecture, to check that it all works ok before manufacture. Gaming heads emulate their fave retro games. Makers of operating systems include emulators of old OS so that customers’ programs largely still work ok: the example they give in the book is Apple emulating the 68000 processor on PowerPC ones; it also occurs to me that the DOS window in Windows OS is an example too.

What to emulate?

The only real answer is the hardware. HW is built to a detailed manufacturing spec, so all the necessary tech details should already exist. You can then install the OS and apps on top (you will have carefully kept all these…)

There’s a good bit on what an AIP actually involves under the emulation approach (p.72). You would need to store

  • the bitstream
  • the SW environment, ie the OS and the app
  • an emulation of the original hardware
  • a manual on how to install the HW, SW, and bitstream, and how they all come together to work.

AA: which strikes me as being a fair bit of work. You really do need to be sure that the documents you are preserving in this way are actually worth all this effort.