ADVENT #18 - #20 — faux floppy
Our last installment was about the 3.5” floppy that once roamed the plains. Actually, that disk also roamed the planes! These disks were widely used in ARINC 615 aircraft data loaders. Though many of these have now been replaced by solid state solutions, you may still see one if you keep a keen eye.
The last element was not a real floppy at all, but the FlashPath adapter which could accept a thin SmartMedia flash memory card and make its contents available through a PC floppy drive using special drivers. This device was a more elaborate version of the cassette adapters for connecting modern media devices to older car stereos.
Smart Media is our first removable media for this installment. I don’t know if you have puzzled this out yet, but half of what I tell you is available on Wikipedia. If I have contempt for something, it’s from my own lived experience but if I’m relating a particular piece of esoterica there is a good chance it’s at least cross-checked with Wikipedia. Speaking of contempt, I always thought SmartMedia was a totally stupid format. It was basically a parallel flash memory chip packaged in a flat semi-rigid plastic card halfway between the telephone SIMs of the era and a credit-card sized smart card. It’s about what you would want a Star Trek isolinear chip to be — big enough that you can show it on screen but small enough that it seems sophisticated. Smart Media was typically around a dozen megabytes — several orders of magnitude below an isolinear chip but an order of magnitude more than a typical floppy.
Because the electrical interface basically matched Toshiba’s own NAND flash memories, the format faded as flash capacity outgrew that package. The MultiMediaCard (MMC) and subsequent SecureDigital (SD) card had a serial interface that seemed slower, but the greater abstraction of the interface allowed them to represent much larger sizes in the same package as flash technology improved.
Our second removable media is the Sony Memory Stick. Really, the less said about this the better. It was essentially the Sony MiniDisc from earlier in this series reimagined as a proprietary, potentially DRM-encrusted flash memory format. I mention it only because the Memory Stick also had a floppy disk adapter. Floppy adapters were also available for SD cards. Probably every other card thinner than a floppy disc had such an adapter, or could be chained through some other flash media converter into an adapter.
These adapters did not convert the contents of the SD card into a typical Microsoft FAT12 floppy disk filesystem. Instead, they took advantage of the relative unsophistication of the floppy disk controller chip on the PC host and worked through device drivers that implemented their own protocol through that. These flash adapters are therefore not drop-in replacements for systems that need a real floppy disk. Legacy floppy systems are often upgraded today with a replacement drive that accepts a USB thumb drive in place of the floppy.
Media adapters were not the only devices to use the floppy interface. The most common way to connect Quarter-Inch Cartridge (QIC) streaming tape backup systems to PCs was through the floppy drive controller. The reduced-size QIC-80 cartridge is our third removable media. These worked with special drivers as well, though they were useful enough that an open-source Linux driver ‘ftape’ was available until around 20 years ago, though the open source means that the details of the interface are still available.
ADVENT #18 — Smart Media
ADVENT #19 — Memory Stick
ADVENT #20 — QIC-80
Tape is near and dear to the Alice system. I got hung up because I wanted to demonstrate the execution trace facility and realized that I had merely satisfied myself that it was possible but I never actually wrote it. Oops. More on that in a future installment. I think it‘s possible to use an Alice tape as a concrete execution before the fact to support a symbolic post process without introducing the needless synchronization between concrete and symbolic typical in on-line concolic systems.