DC100
Encyclopedia
The DC100 tape format and drive was developed by Hewlett-Packard
and introduced as a data storage mechanism for the HP-9825 programmable calculator. The DC100 tape cartridge was a scaled down version of the DC300 cartridge pioneered by 3M, and represents an early version of what is now referred to as the QIC Mini Cartridge
This format was used in the HP series 80
calculator/computer systems of the late 1970s and early 1980s. It was also used in the HP 2640
series of computer terminals.
The DC150 cartridge, a variation with slightly higher capacity, was used in Digital Equipment Corporation
's DECtape II
drives.
The DC100 tape is based on the 1972 patent number 3692255.
DC100:
3M manufacturing secrets.
HP improvements on the 3M design;
3M
developed the DC300 tape cartridge for loading programs into AT&T
’s electronic switching systems that were becoming the backbone of the world’s phone system in the 1970s.
QIC minicartridges evolved it's capacity from 250 Kbyte, 40, 80, 120, to a final 250 MByte.
QIC-3230 tapes have a maximum.
Hewlett-Packard
Hewlett-Packard Company or HP is an American multinational information technology corporation headquartered in Palo Alto, California, USA that provides products, technologies, softwares, solutions and services to consumers, small- and medium-sized businesses and large enterprises, including...
and introduced as a data storage mechanism for the HP-9825 programmable calculator. The DC100 tape cartridge was a scaled down version of the DC300 cartridge pioneered by 3M, and represents an early version of what is now referred to as the QIC Mini Cartridge
This format was used in the HP series 80
HP series 80
The Hewlett-Packard series 80 of small scientific desktop computers was introduced in 1980, beginning with the popular HP-85 targeted at engineering and control applications. They provided the capability of the HP 9800 series desktop computers in a smaller package including storage and printer, at...
calculator/computer systems of the late 1970s and early 1980s. It was also used in the HP 2640
HP 2640
The HP 2640A and other HP 264X models were block-mode "smart" and intelligent ASCII standard serial terminals produced by Hewlett Packard using the Intel 8008 and 8080 microprocessors.-History:...
series of computer terminals.
The DC150 cartridge, a variation with slightly higher capacity, was used in Digital Equipment Corporation
Digital Equipment Corporation
Digital Equipment Corporation was a major American company in the computer industry and a leading vendor of computer systems, software and peripherals from the 1960s to the 1990s...
's DECtape II
DECtape
DECtape, originally called "Microtape", was a magnetic tape data storage medium used with many Digital Equipment Corporation computers, including the PDP-6, PDP-8, LINC-8, PDP-10, PDP-11, PDP-12, and the PDP-15. On DEC's 32-bit systems, VAX/VMS support for it was implemented but did not become an...
drives.
The DC100 tape is based on the 1972 patent number 3692255.
| Generation | DC100 | DC200 | DC300 |
|---|---|---|---|
| Release date | 1975 | 1972 | |
| Native capacity | 210 kB | 2.9 MB | |
| Max speed | 650 B/s | ||
| Tape length | 140 ft (42.7 m) | 400 ft (91.5 m) | |
| Tape width | 0.150 in | 0.25 in | |
| Data density | 1600 bpi | ||
| Tracks | 2 | ||
| Coercivity | 310 Oe Oersted Oersted is the unit of magnetizing field in the CGS system of units.-Difference between cgs and SI systems:... |
DC100:
- Fast Access Cartridge Transport (FACT)
3M manufacturing secrets.
- Base plate flatness.
- Guide posts (essentially the 5 "axles" in the cartridge) into the base plate with sufficient perpendicularity.
- Guide-post surface finish. Too rough, abraded the back of the tape. Too smooth, tape adheres to the guide through stiction, which causes speed flutter on the tape. The right surface treatment was found to be lapidary tumbler, a recipe of abrasive and burnishing compound.
- Guide-post perpendicularity had to be right to avoid differential tension on the tape. In the sever case contact between tape and head was lost. The two most critical guide posts in the manufacture fixture, the hub bearing or axle posts, had to be perpendicular to within approximately 1/3° degreesDegree (angle)A degree , usually denoted by ° , is a measurement of plane angle, representing 1⁄360 of a full rotation; one degree is equivalent to π/180 radians...
. - Lubrication.
- Cartridge’s internal plastic drive belt (critical).
HP improvements on the 3M design;
- Tape tension is controlled primarily by friction in two rollers that the belt loops around. 3M controlled belt-roller friction (and hence the tape tension) with a very precise amount of STP lubricant on the bearing surfaces. A better design was to use large axles and Teflon-filled plastic for the for the bearing rollers, which eliminated the need for lubrication.
- Minimum tape tension at the head was increased, the drive force to spin the drive puck was less however.
- Optical sensing of cartridge in and write protect.
- DC200 tape cartridge used a thinner tape to increase the amount of data over DC100.
3M
3M
3M Company , formerly known as the Minnesota Mining and Manufacturing Company, is an American multinational conglomerate corporation based in Maplewood, Minnesota, United States....
developed the DC300 tape cartridge for loading programs into AT&T
AT&T
AT&T Inc. is an American multinational telecommunications corporation headquartered in Whitacre Tower, Dallas, Texas, United States. It is the largest provider of mobile telephony and fixed telephony in the United States, and is also a provider of broadband and subscription television services...
’s electronic switching systems that were becoming the backbone of the world’s phone system in the 1970s.
QIC minicartridges evolved it's capacity from 250 Kbyte, 40, 80, 120, to a final 250 MByte.
QIC-3230 tapes have a maximum.
See also
- Quarter-inch cartridge (QIC)
- Compact CassetteCompact CassetteThe Compact Cassette, often referred to as audio cassette, cassette tape, cassette, or simply tape, is a magnetic tape sound recording format. It was designed originally for dictation, but improvements in fidelity led the Compact Cassette to supplant the Stereo 8-track cartridge and reel-to-reel...
- Same width as DC100 - HP 2644AHP 2640The HP 2640A and other HP 264X models were block-mode "smart" and intelligent ASCII standard serial terminals produced by Hewlett Packard using the Intel 8008 and 8080 microprocessors.-History:...
- Introduced with DC100 - HP 9800 series desktop computers - Computers used with DC-series tape
