He means a WLIW system with a 1,024-bit (1-kibibit) instruction set. This is along the lines of 4-bit (e.g. pocket calculators) → 8-bit (e.g. Commodore 64) → 16-bit (e.g. Intel 8086) → 32-bit (e.g. IA-32 / x86-32 / i386 / x86) → 64-bit (e.g. x86-64 and IA-64) → ... system development, to which there are exceptions.
On January 19, 2038 [...] at 3:14:07 GMT, UNIX will be exactly 1 billion seconds old
UNIX was created in 1969, not on January 1, 1970 at 0:00:00 UTC (not GMT; GMT was equal to UT untill the introduction of UTC) - the UNIX epoch was chosen to be a round date and time, which is not even the start of the 1970es decade. 1 billion seconds since the UNIX / POSIX epoch occurred on September 9, 2001 at 01:46:40 UTC, not on January 19, 2038 at 03:14:07 UTC. Also, 2^32 (4,294,967,296) seconds since the UNIX / POSIX epoch will occur on January 19, 2038 at 03:14:0
8 UTC - this is the time at which software on 32-bit UNIX / POSIX systems will start experiencing problems - if you want to know what kind, just set a 32-bit UNIX / POSIX systems' hardware clock to January 19, 2038 at 03:00:00 UTC, reboot, and see what happens. 2^64 (18,446,744,073,709,551,616) seconds since the UNIX / POSIX epoch will occur on December 4, 292,277,026,596 at 15:30:08 UTC - this is the time at which software on 64-bit UNIX / POSIX systems will start experiencing problems; however, this will not be a problem for anyone on Earth as the Sun will enter a red giant phase in 5 billion years and will have a maximum radius beyond the Earths' present orbit - meaning it will burn, melt, and swallow the Earth - 64-bit UNIX / POSIX systems beyond the Solar system can, however, remain fully operational for another 287 billion years.