lines could be 0 to 15 per line (Due to interlacing a physical scan was two pixels high), configurable horizontal resolution per line, using indexed colors, limit modifying the color palette to one color per line. In 4 color mode, per logical line one foreground and one background color could be selected, so each line element or logical pixel could be represented by one bit. In 16 color mode, the color palette was inherited from the previous line. only one of the four usable colors could be changed. These graphical limitations were handled by BASIC "so the user didn't notice his feet were tied together". BASIC allowed only the whole screen in one mode, but poking directly in memory allowed mixed resolution lines. The whole PGG was implemented with two PROMs and standard TTL logic. The scheme predated the Amiga HAM mode by half a decade. The BASIC interpreter was remarkably fast for the time because it pre-compiled to an internal byte-code, unlike the Microsoft BASIC interpreter which most other systems of the time used. DAI variables could be up to 14 characters long. The internal byte code used pointers to a variable look up table at the bottom of the code, which made the code extremely compact, despite long variable names. This technique was rare (only other known examples are the ABC 80 and BK-0010), and is remarkably similar to that now used for Java. To enhance the mathematical abilities of BASIC, (and assembler programs) an AMD AM9511 floating point co-processor (compatible with the Intel 8231) could be added. The first working example was produced in less than 3 months, by 3 people, one of whom was taping up the circuit board layout. All 64K of assembler was the work of one man David Collier, and all the hardware design the work of another David, David Lockey. The original decision to use the 8080A 1 MHz processor (already in use by DAI on other products) was forced by the timescale, which itself was dictated by a desire to show the machine to a TI USA board meeting. In the end, only a flight on a Concorde got the machine there on time. However, the slow CPU dictated a huge amount of work on the pre-compiling BASIC and the option for hardware-assisted floating point which might not have been required if the newer Z80 had been chosen. The decision to