Tuesday, 3 April 2018

QL Tetroid Gold Card clone

Last year, I was so eager to get Tetroid's Disk Interface for the QL I didn't notice Tetroid's Miracle Gold Card clone - that would have been more interesting for me. I cursed myself a bit, waited for some time, then decided to order it anyway.

The Gold Card has a 68000 processor, a floppy disc interface, battery for backing up the clock/date and 2 megabytes of memory. I had a slow moment, thinking, "How can this be, the QL cannot address more than 1MB?" But of course the 68000 can access more memory than the 68008, that's the whole point.

The speed increase (~4x they say) is the main reason I was interested in the Gold Card. The speed is not about processor frequency, it's just that the 68000 does not need to "convert" 16/32 bit instructions to a 8-bit data path the way the 68008 does.

Theoretically, if a program is coded in a way that avoids 68008 bottlenecks, it might not be radically faster on the 68000.

The even faster Super Gold Card is probably eventually going to be cloned too (I'm hoping), but I just could not wait.

Unlike the Tetroid Disk Interface (TDI), there is no Compact Flash card reader built in. The Gold Card has a floppy disk interface which together with my HxC Floppy Emulator is enough for loading programs from an SD card. But the card seems to work well with the QL-SD and Minerva ROM, so I can have both FLP and SDC connected.

To make the difference between the three products clearer, I've created this table:

                      TDI      GC       QL-SD
Card Reader:          YES(CF)  NO       YES(SD)
68000/Acceleration:   NO       YES      NO
Memory:               800K     2MB      NO *)
Disk interface:       YES      YES      NO
Battery-backed clock: NO       YES      NO
Toolkit 2:            YES      YES      NO
Minerva ROM:          NO       NO       YES

*) The file allocation table takes memory

The QL-SD is not really comparable, but I included it to make clear how these devices might complement each other. Note also that none of the solutions enable a direct file-transfer between a PC/MAC file system and the card reader.

Looking at the Gold Card board, it is the same professional quality as the TDI. Installing was easy. There are no jumpers or settings to consider, nothing to screw or un-screw, just remove the extension port cover and push the card in gently along the rails.

The card is a bit longer than the TDI, although it does not extend over the computer footprint.

When connected, take care: Do not grab the card when picking up the computer, as this can bend the boards inside.

Booting & BASIC test drive

Although the booting sequence must be technically faster, there is also more memory to check and therefore it takes a tiny while. Then I get the "Gold Card v 2.49" message and I'm off to superBASIC.

With the Minerva ROM, I have to look at the added boot option screens - the QL-SD also needs a short waiting time. For some reason I had to do my mode selection "twice" if I go for the F4/Dual screen. But the Minerva boot and memory check have been optimized so it's pretty quick.

It's instantly clear the speed makes it much more pleasurable to work in the BASIC environment. I no longer have a feeling the system stays behind my moves. Before the upgrade, all listing, editing, typing, scrolling and similar actions were about bearable, now they are quite slick.

Again, TK2_EXT activates the Toolkit 2 extensions (the command itself is faster) and after that you can use the semi-fullscreen editor ED, FSERVE file server, or use WTV to set the BASIC window size to work better with a television.

Just eyeballing a couple of BASIC graphics routines shows the 4 x speed increase is quite real. Testing also highlights how slow the SuperBASIC is to begin with, so I'll have to say even now the BASIC does not give lightning-fast graphics.

When comparing an unexpanded QL with a Minerva ROM+68000, not all speed increases are due to the processor, as Minerva improves the ROM routines a bit. Taken together, SuperBASIC on Minerva+68000 is clearly 4 times faster and even more.

For example, the following line-drawing test could finish nearly 7 of the 8 color sweeps before the unexpanded QL without Minerva could finish even one.

100 MODE 8
110 PAPER 0: CLS
120 FOR I=0 TO 7
130 INK I
140 FOR Y=0 TO 100
150 LINE 0,0 TO 100,Y
160 NEXT Y
170 NEXT I

With output something like this.
QED text editor is smoother and begins to remind me of typing on ST/Amiga editors. My QMAC compiler setup works faster, and I guess the file access from RAM drive should also benefit from the acceleration.

The Qliberator-compiled BASIC increases the speed further. The compiler by itself does not do that much and my rough estimate is that even the non-compiled BASIC on 68000+Minerva is faster than compiled programs were on a completely unexpanded QL.

There are probably accurate benchmarks and testing software around, but this kind of simple observations are enough for me.

Final remarks

Decades after, it's easy to say that a full 68000 is what the QL should have had in the beginning. But old 68000 processors were costly and they also took up room on the board (64 vs 48 pins). QL would have jumped to a different price category and likely eaten up more desk space. The 68008 helped to make a very cheap and tiny computer with enough 16-bit sensibilities, yet more portable than many "portables" were back in the day.

But what about the Miracle Card Clone in this day and age? Because the card has a processor, memory and a disk interface, maybe Tetroid might clone a full computer, integrate the (Super) Gold Card and fit it all inside original QL case and connectors? That would be wonderful.

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