nova

Webster's Dictionary (1913)

Origin: L., fem. sing. of novus new.

Astronomy A star which suddenly increases in brightness thousands of times, then fades back to near its original intensity. It may appear as a “new” star if its original brightness was too low for routine observation. A star which suddenly increases in brightness to many millions of times its original intensity is a supernova, and the postulated mechanisms for the increases of brightness of novae and supernovae are different. The most important modern novae are: — No"va Co*ro"nae Bo`re*a"lis (…) [1866]; No"va Cyg"ni (…) [1876]; No"va An*dro"me*dae (…) [1885]; No"va Au*ri"gae (…) [1891-92]; No"va Per"se*i (…) [1901]. There are two novae called Nova Persei. They are: (a) A small nova which appeared in 1881. (b) An extraordinary nova which appeared in Perseus in 1901. It was first sighted on February 22, and for one night (February 23) was the brightest star in the sky. By July it had almost disappeared, after which faint surrounding nebulous masses were discovered, apparently moving radially outward from the star at incredible velocity.

Webster’s Revised Unabridged Dictionary (1913), from GCIDE 0.54 · with additions: +PJC, 1913 supplement

Free On-line Dictionary of Computing

<processor> A minicomputer(?) introduced by Data General in 1969, with four 16-bit accumulators, AC0 to AC3, and a 15-bit program counter. A later model also had a 15-bit stack pointer and frame pointer. AC2 and AC3 could be used for indexed addressing and AC3 was used to store the return address on a subroutine call. Apart from the small register set, the NOVA was an ordinary CPU design.

Memory could be accessed indirectly through addresses stored in other memory locations. If locations 0 to 3 were used for this purpose, they were auto-incremented after being used. If locations 4 to 7 were used, they were auto-decremented. Memory could be addressed in 16-bit words up to a maximum of 32K words (64K bytes). The instruction cycle time was 500 nanoseconds(?). The Nova originally used core memory, then later dynamic RAM.

Like the PDP-8, the Data General Nova was also copied, not just in one, but two implementations - the Data General MN601 and Fairchild 9440. Luckily, the NOVA was a more mature design than the PDP-8.

Another CPU, the PACE, was based on the NOVA design, but featured 16-bit addresses (instead of the Nova's 15), more addressing modes, and a 10-level stack (like the Intel 8008). [Speed, mini?]

(2003-10-23)