Re: Virtual serial drive

[Kevin <kevin@hackaday.com>]

On Tuesday, October 2, 2012 3:47:25 AM UTC-5, Michael J. Mahon wrote:
> Kevin <kevin@hackaday.com> wrote:
> 
> > I have a almost working model of the host on a AVR + SD card +
> 
> > breadboard, its all talking, its agreeing on the cheksum, its almost
> 
> > reading but I only get an hour or two here and there.
> 
> > 
> 
> > but for a sanity check its all looking pretty good, get all the software
> 
> > going, work out the details, spin a board, and have a virtual serial
> 
> > drive backpacked, free of pc tether, on my //c before November
> 
> > 
> 
> > as I get things more worked out I will start publishing stuff, right now
> 
> > its just a ball o wires and some horrid brute force code.
> 
> 
> 
> You certainly have my interest!
> 
> 
> 
> Sounds like a great way to get a 115kb connection to an SD "hard disk" with
> 
> a IIc+. ;-)
> 
> 
> 
> -michael - NadaNet 3.1 and AppleCrate II: http://home.comcast.net/~mjmahon

Well thats a bit more incentive to do it =) few things keep mulling in my head, maybe since you were silly enough to show interest you could chime in.

Power: how am I going to get sufficient power to the thing, SD spec calls out for 200mA, and while I know no modern card living in the back of a apple II is going to eat that much, its not going to stop someone from popping in a 12 year old 32 meg card that might. Simple wall wart would solve this but its another thing to plug in. Tapping off the ports on the machine is another option, but then you have this thing snaking all over the place, possibly blocking off something useful, and connectors are not cheap compared to the rest of the board. 

Clock: its trivial to plop in a RTC, and the one I am eyeballing is like 86 cents a pop, but it adds a layer of complexity just to set the thing to one's local time ... and a battery (or supercap). The thought was I make a utility disk that goes over "normal" serial to the AVR, or just leaving the date/time stamps as zero.

Multiple images: using ADT you can sneak into a file manager, remove your current disk, plop in a new "virtual.po" file and no one is the wiser. I kind of like that feature. If I make the aforementioned utility disk you could boot to that, set I dunno 5 slots? and when you wanted to switch volumes hit a button on the box. another option is have a device on the side with a LCD screen. That almost instantly doubles the BOM cost. keeping in mind that I currently have the BOM at around 20 bucks not counting PCB and actual card.