" the restriction to only very small boards makes it practically unusable." Yeah, the pincount restriction of diptrace is much more sensible than an area restriction. I have no idea what you plan to program for that machine, but to me 256K..1024K already seem very generous for that machine. Maybe you could design your bank switching scheme such that it is expandable with more mini boards of 256..1024K, and you try first with one and see whether it's enough - don't have to solder everything until you know it's needed. You could, at startup, detect the presence of each possible module by writing/reading back a bit pattern to the highest address byte or so, to know how much is installed.

Looks nice :-D Never heard of it. But what the heck would that thing do with all that Memory? :-D Well. Have you soldered SMT before? The SO package is just 1/2 of the usual 0.1" pin spacing, if you're really bored you could even get that on perfboard, splitting pads - but I guess you wouldn't want to handwire that mess then :-D Entirely possible with thin "coil wire", but pretty dull work. Do you have a PCB layout program? If not, or you hate the one you have - try the lite version of DipTrace (and if you mail them confirming this is for non-Profit use, you'll get a code to up the pin limit from 300 to 500 per board). If you tried EAGLE and hate it - welcome aboard, try DipTrace ;-) As said, SO package is a piece of cake, also not so painful routing wise when you have only two layers (max of what free diptrace supports). But if you don't have many traces crossing due to clever placement, rotating & layout, maybe you'd even manage smaller packages with 2 layers. The soldering of smaller packages is done differently from the big ones. You don't usually solder individual Pins, but several pins at a time, or even all in one drag movement. Look on YouTube for tutorials on "drag soldering SMT". Rule 1) apply lots of flux, Rule 2) don't forget to add some more flux! ("no-clean" flux, if you don't want a mess) If you still accidentally create a solder bridge between pins, this can be removed with fine solder wig and - flux! I'd not recommend putting a blob of solder, bridging lots of pins "on purpose" and then removing surplus with wig, though. Some ppl do that as it seems easier than practising drag solder or soldering ~3 pins at a time with a usual chisel tip (my preferred) - but more mass of hot metal means increased likelyhood of killing the IC. For drag soldering & generally doing fine pitched stuff to work, you need to do your PCB with a solder mask layer (usually created by the CAD Software, but parameters Need to be adjusted to design rules of PCB manufacturer) Then oshpark makes good quality PCBs, for 2-layer I think it's $ US 5,- per square inch, for 3 PCBs of that design. So smaller is cheaper, and since with those many same ICs you probably have quite some repetition in circuit, the "3 PCBs of 1 design" may be exploited nicely, when several identical smaller boards are made, maybe then pluggin into a main board that connects to your computer. (if that "3 PCBs" rule bothers you, I don't know international PCB fabbers with good price, sorry)

What "old computer" that came with 4Kbytes can be made using 16Mbytes? And with 32x 512KB modules? *scratches head*

Why? Through-hole parts are still available reasonably priced. But anyway. I use SMT parts on perfboards for trying out circuits all the time. 1206 resistors & caps are *huge*, even if tweezers are needed to solder that, even beginners should have no trouble using them or 0805 parts, which fit exactly between two copper pads with 0.1" spacing.

C64, at first with NO storage, as I got it from a school buddy at 12..13 years or so, but his FDD was broken. So I learned BASIC from the manual and wrote little programs, each day a new one :D Until I got a floppy drive from someone else weeks later. Interestingly it came with a mouse. So I learned a bit asm and wrote a IRQ based "mouse driver" moving a HW sprite arrow around, something I'd seen on a PC at a buddy's house ^^ As for PCs, it was a Tandon PC XT, 5MHz, 640KB RAM, no hdd, dual 5.25" floppy, monochrome orange monitor, MSDOS 3.2 or so. With GWBASIC, ugh ^^ The school had dumped it, so I thought, let's try a real PC.

No, I started about 12..13 years of Age, with a C64 & BASIC / asm, when many Kids in School already had an Amiga or 286/386 PC or so, didn't have the dough for "a real computer" as I was told to rather buy. As for VS2013, not using it yet. But when I heard MS hired the then head of the Eclipse team, I involuntarily emanated a scream of agony into the night, for I knew, the fate of my beloved tool of choice was sealed. ( hah I don't know how bad it really is and what the guy had to do with it, but still, MS, what were you thinking ;) )

And those would surely like to drink some Peniscola