Well, it was cool when I got it. The original 48K rubber keyed spectrum was the first computer we owned first hand. Prior to that had an upgraded zx81 (rehoused in a 3rd-party proper keyboard unit and 16KB Ram Pack) that was previously my uncle's.
In comparison to the rehoused '81 it was so sleek looking. Quick and dirty BASIC programs seemed to run significantly faster, you could get colours, "high res" (256x192 :lol:) modes and sound (1-bit beeping). It was damn cool.
The manuals that came with it were exceptionally cool. They were proper ring-bound and written with some humour too. They also contained useful appendices that covered the memory map and Z80 instruction set. Having already learnt a bit of Z80 on the ZX81 it wasn't long before I was able to do some freaky things. Despite the 1-bit resolution, I was able to write a small sound record/playback routine that basically read the mic socket state at a much higher rate than usual. It was actually possible to get some recognisable audio out of it, but you couldn't store a lot between the top of the BASIC area and the area where I'd located the routine (for speccy users, it was just below the normal UDG).
The games were just awesome, at least compared to anything on the ZX81 at the time.
As for peculiarities, the way the display area was arranged was just bizarre. You had a single bit plane, starting at address 0x4000, which had a resolution of 256x192, thus occupying exactly 6KB.
Ok, so that's not unusual, anybody that understands how the Amiga graphics system works is totally fine with bit plane graphics. What made it unusual was the way it was layed out. As you accessed successive 32-bit spans, you got scan lines 0, 8, 16, 24, 32, 40, 48 and 56, next you got scan lines 1, 9, 17, 25, 33, 59, 57 and so on, until you got 7, 15, 23, 31, 39, 37, 55 and 63. Then this sequence would repeat for scan lines 64 - 127, then finally once more for scan lines 128-191.
After that came a 768 byte "attribute" buffer that defined a 32x24 character grid on top of this. Each cell had a 3-bit foreground colour (applied to any set bit in the bitplane within that cell), a 3-bit background colour (applied to any clear bit in the bitplane within that cell), a 1-bit "bright" attribute and a 1-bit "flash" attribute.
The 3-bit colour values basically gave colours in order of brightness, so they were 0:black, 1:blue, 2:red, 3:magenta, 4:green, 5:cyan, 6:yellow, 7:white. These colours were only about 70% bright. If the "bright" bit was set, you got a brighter version of the colour which was fully bright. If the "flash" bit was set, the foreground and background colours would invert on a 2Hz interrupt (IIRC).
A side effect of this display layout was that you only got 2 discrete colours for each 8x8 pixel block on screen. This lead to a lot of "colour clash" in games, where sprites would partially change colour when some of their pixels ended up in a neighbouring cell.
As for what I miss? Actually nothing. I still have a fully working 48K ZX Spectrum that I can fire up whenever the mood takes me
