On 2019-09-17 10:20 a.m., D. Hugh Redelmeier via talk wrote:
- when they are gone, they are gone. This means that one should not use these in a project that expects system replication over time. [Few of my projects are intended to be replicated.]
A wise person once told me “Don't specify surplus”, and that's served me well. I see so many maker projects that are based on a critical component that was available as surplus. These are dead projects now. (example: Active Surplus used to have a good-sized alphanumeric display available for 50¢. They came with no datasheet and had a distinctive 1.27 mm pitch not-quite-flexible ribbon cable. Turns out that this display had a very strange clocking requirement that relied on a long-superseded driver chip. Getting anything to display on it at all was extremely difficult even with a fast microcontroller.)
Those are useful labels for consumers (which we are). I thought you had some technical issues in mind.
Turns out that you can get much higher rates in benchmarks with certain cards and a Raspberry Pi 4, but in day to day mixed use, there's not much in it. It seems confusing: https://www.jeffgeerling.com/blog/2019/raspberry-pi-microsd-card-performance...
- the first MMC cards were dead simple to read and write. I think that a simple parallel port could do it (slowly). One data pin!
Note that this is still the way you have to do it, unless you want to buy a licence from the SD Association.
I daydreamed about adding a disk to my Altair using this simple interface.
Josh Bensadon, a local retro computer guru, recently made a whole new S100 CPU card with an SD card for storage. It's only as fast as the 2 MHz 8080A can move data, though: http://www.s100computers.com/My%20System%20Pages/8080%20CPU%20Board/8080%20C... cheers, Stewart