Subject: Re: 1Tbit 'laser optical recording medium' From: paulkoning at comcast.net Date: Mon, 14 Oct 2013 14:30:40 -0400 To: cctalk at classiccmp.org Sounds a bit like the write-once optical disk cartridge disk DEC made at one time (forgot the model number). But a terabit (128 GB) seems like an implausibly high storage density for an early 1970s storage device. That's almost 3 orders of magnitude larger than disk drive densities of that time, not even considering the fact that it says "a disk" while dense disk drives at the time had perhaps 10 platters. The obvious conclusion is {{citation needed}} . paul On Oct 14, 2013, at 1:33 PM, JP Hindin <jplist2008 at kiwigeek.com> wrote:

from an argon laser records binary data by burning microscopic holes

>>> While reading the wikipedia article on the ILLIAC IV there's a curious >>> excerpt relating to the disk media: >>> >>> "They also provided a Burroughs B6500 mainframe to act as a front-end >>> controller. Connected to the B6500 was a laser optical recording medium, a >>> write-once system that stored up to 1 Tbit on a plastic disk covered with >>> a thin metal film."

In the IEEE paper BOUKNIGHT et al: THE ILLIAC IV SYSTEM, April 1972 there is this paragraph: BEGINQUOTE 1) Laser memory: The B6500 supervises a 10^12-bit write-once read-only laser memory developed by the Precision Instrument Company. The beam from an argon laser records binary data by burning microscopic holes in a thin film of metal coated on a strip of polyester sheet, which is carried by a rotating drum. Each data strip can store some 2.9 billion bits. A "strip file" provides storage for 400 data strips containing more than a trillion bits. The time to locate data stored on any one of the 400 strips is 5 s. Within the same strip data can be located in 200 ms. The read and record rate is four million bits per second on each of two channels. A projected use of this memory will allow the user to "dump" large quantities of programs and data into this storage medium for leisurely review at a later time; hard copy output can optionally be made from files within the laser memory. ENDQUOTE The "10^12" is written as 10 superscript 12, I've shown it with caret notation. cheers, nigel. Unabashed Burroughs B5XXX/6XXX fan :-) with a wistful eye to the ILLIAC IV >>>> While reading the wikipedia article on the ILLIAC IV there's a curious >>>> excerpt relating to the disk media: >>>> >>>> "They also provided a Burroughs B6500 mainframe to act as a front-end >>>> controller. Connected to the B6500 was a laser optical recording medium, a >>>> write-once system that stored up to 1 Tbit on a plastic disk covered with >>>> a thin metal film."