Replying to a message of Phil Payne to Robert Comer:

 PP> From: Phil Payne 

 >>> Once a month should be enough from now on.

 >> SR-71's overflew Vietnam far more frequently than that.

 PP> Erm - yes.

If memory serves, and I was *there* (Kadena AB, Okinawa, where the SR-71's
were based), the black birds flew missions two or three times a week.  Not
all of them were to Vietnam, though.

 PP> a) What was the state of digital image analysis
 PP> technology thirty years ago?

I don't think they had digital image analysis during the Vietnam era.

 PP> b) How much did a gigabyte of disk storage cost?

Probably as much as and probably more than the average house of the time.  

The first mainframe computer I worked on was a Honeywell H-6000.  Top of
the line, state of the art late 1960's/early 1970's.  Memory storage
capacity was 256KB words (a word being 36 bits in that architecture rather
than the 32 bits in the IBM world), basically *one* megabyte.  Six
Honeywell DSS191 removable pack hard disks (IBM 3330 equivalent), if memory
serves about ten megabytes each; six nine track round tape drives (one tape
= 1800 feet at 1600 bits per inch - later 6250 bits per inch).  Hardware
cost well into six digits and maybe into seven.
By comparison, the obsolete desktop computer I'm using right now (IBM
PC-350. 100Mhz Pentium) has 128MB of memory, ten gigs of hard drive space
and a 4mm tape backup system - and represents a total investment of less
than $500.

---