DF-224
Encyclopedia
The DF-224 is a space-qualified computer
used in space missions from the 1980s. It was built by Rockwell
Autonetics. As with many spacecraft computers, the design is very redundant, since servicing in space is at best difficult and often impossible. The configuration had three CPUs, one active and two spares. The main memory consisted of six memory units, each with 8K 24-bit words of plated wire memory, with up to 48,000 words total. Four memory modules could be powered up at one time, resulting in a maximum of 32K of available memory, though some applications such as the Hubble Space Telescope
used fewer memory banks to allow for graceful failure modes
. There were three IO processors, one operational and two backups. The power supply consisted of 6 independent power converters, with overlapping coverage of the operating functions.. The processor used fixed-point arithmetic
with a two's complement
format.
By the standards of 2010, the computer was rather big and slow. It was roughly 45 centimetres (1.5 ft) by 45 centimetres (1.5 ft) by 30 centimetre (0.984251968503937 ft), weighed 50 kilograms (110.2 lb), and had a clock speed of 1.25 MHz. According to a Hubble servicing mission report, when the DF-224 was replaced by a 25 MHz Intel i486
, processing power increased about 20x.
Computer
A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...
used in space missions from the 1980s. It was built by Rockwell
Rockwell International
Rockwell International was a major American manufacturing conglomerate in the latter half of the 20th century, involved in aircraft, the space industry, both defense-oriented and commercial electronics, automotive and truck components, printing presses, valves and meters, and industrial automation....
Autonetics. As with many spacecraft computers, the design is very redundant, since servicing in space is at best difficult and often impossible. The configuration had three CPUs, one active and two spares. The main memory consisted of six memory units, each with 8K 24-bit words of plated wire memory, with up to 48,000 words total. Four memory modules could be powered up at one time, resulting in a maximum of 32K of available memory, though some applications such as the Hubble Space Telescope
Hubble Space Telescope
The Hubble Space Telescope is a space telescope that was carried into orbit by a Space Shuttle in 1990 and remains in operation. A 2.4 meter aperture telescope in low Earth orbit, Hubble's four main instruments observe in the near ultraviolet, visible, and near infrared...
used fewer memory banks to allow for graceful failure modes
Fault-tolerant system
Fault-tolerance or graceful degradation is the property that enables a system to continue operating properly in the event of the failure of some of its components. A newer approach is progressive enhancement...
. There were three IO processors, one operational and two backups. The power supply consisted of 6 independent power converters, with overlapping coverage of the operating functions.. The processor used fixed-point arithmetic
Fixed-point arithmetic
In computing, a fixed-point number representation is a real data type for a number that has a fixed number of digits after the radix point...
with a two's complement
Two's complement
The two's complement of a binary number is defined as the value obtained by subtracting the number from a large power of two...
format.
By the standards of 2010, the computer was rather big and slow. It was roughly 45 centimetres (1.5 ft) by 45 centimetres (1.5 ft) by 30 centimetre (0.984251968503937 ft), weighed 50 kilograms (110.2 lb), and had a clock speed of 1.25 MHz. According to a Hubble servicing mission report, when the DF-224 was replaced by a 25 MHz Intel i486
Intel 80486
The Intel 80486 microprocessor was a higher performance follow up on the Intel 80386. Introduced in 1989, it was the first tightly pipelined x86 design as well as the first x86 chip to use more than a million transistors, due to a large on-chip cache and an integrated floating point unit...
, processing power increased about 20x.
See also
- IBM RAD6000 - a more modern space-qualified computer.
- RAD750RAD750The RAD750 is a radiation-hardened single board computer, based on IBM's PowerPC 750. The successor of the RAD6000, the RAD750 is manufactured by BAE Systems Electronic Solutions. It is intended for use in high radiation environments such as experienced on board satellites and spacecraft...
- newer version - Mongoose-VMongoose-VThe Mongoose-V 32-bit microprocessor for spacecraft onboard computer applications is a radiation-hardened and expanded 10–15 MHz version of the MIPS R3000 CPU. The Mongoose was developed by Synova, Inc...
- radiation hard processor based on the MIPS-3000. - Various implementations of the MIL-STD-1750A 16-bit processor have been used in several spacecraft