ENCHTEST NeXT The NeXT Computer System is very close to what designer Steve Jobs promised three years ago, and he is confident that it will be the micro for the next decade. Owen Linderholm says it's a breakthrough in price and power and may set an important standard. Page 38 APC 100th Issue BENCHTEST When Steve Jobs left Apple three years produced before; one of the reasons the monitor power, mouse, keyboard and ago and announced that he was going to final product is so cheap. sound signals. The monitor (only one is build the NeXT thing in computers, he The system software is based on the currently available) is black and hooks wasn't given much chance to succeed. Mach multi-processing version of Unix. up to this with a 3m cable. It has a 17in But the NeXT Computer System is finally Display PostScript is used to display a display and shows 1120 by 832 pixels in here. It has long been known to be in- lightning-fast and very powerful graphi- four grey scales, giving it an on-screen tended as a Unix-based academic cal user interface with windows, menus, resolution of 92dpi. It rests on an er- graphics workstation. However, it took so icons and object-orientated features. gonomic stand, which is adjustable for long to arrive that several other com- It was designed in conjunction with an height and can tilt and swivel. The panies, notably Sun and Apollo, got well advisory board from US universities and stand's wheels allow it to be easily ahead in the field. colleges, and the collaboration shows in moved around on a desktop. The Out of the rumours, a few facts about much of the design. The digital signal monitor also has a small speaker. the NeXT computer surfaced. It would processor can be used for real-time data The keyboard connects to the base of use Display PostScript, a display version analysis, the 8Mbytes of RAM and the monitor and is also black, as is the of the image control language Post- 256Mbytes of disk storage provide mouse. Other connectors on the monitor Script, for screen output; it would have ample space for research work and include a stereo headphone jack, two especially good sound quality and con- volumes of data. The operating system stereo connectors for hookup to external trol built in; the processor would be the is based on Berkeley Unix, the academic audio equipment and a microphone jack. Motorola 68030; and the operating sys- standard, and a huge range of valuable The keyboard has 84 keys, including tem would be loosely based around the research software is bundled with the cursor keys, a numeric keypad, a power Mach version of Unix. computer. on-and-off key (the only on/off switch for The real thing, much to everyone's the computer) and two keys to control surprise, has turned out to be very close volume and screen brightness. There to what Jobs promised all along. It in- Hardware are two Alt and two Command keys on cludes a coprocessor and a digital signal The computer is a matt, 30cm mag- either side of the main keyboard. The besides the 68030, all clocked at nesium cube. It has stylish industrial mouse plugs into the keyboard complet- 25MHz, giving it a processing speed of design ventilation grilles on all sides. ing a long daisy chain. It is a two-button five mips. The only other features on the cube are mouse, but the buttons are small and The most dramatic of its features is two panels on the front for mass storage awkwardly placed. the first erasable optical drive, storing a devices, one taken up by the optical NeXT's own laser printer is a 400dpi staggering 256Mbytes. The main circuit drive with a wide slot showing; the NeXT unit using a modified Canon SX engine. board is a masterpiece of design, is logo at the bottom; the universal power It is smaller than most current 300dpi very densely packed and uses surface supply connector at the back; and a laser printers and is designed to reduce mount techniques wherever possible. cluster of ports along the bottom at the paper jams. The printer also has a Even more amazingly, every single back. 300dpi mode, or 'draft' quality as Steve component apart from one is imple- There are seven ports at the back — Jobs described it. It has a universal mented in CMOS, meaning that it two are 8-pin serial ports. There is also a power supply and a paper feed operates more coolly and uses con- standard coaxial connector for Ethernet, mechanism that can automatically hand- siderably less power. a 9-pin serial port for connecting to the le different sized paper and envelopes. The board is made by an automated NeXT Laser Printer, a SCSI (pronounced Naturally, the printer is also matt black. assembly line and is untouched by `scuzzy) connector and a 15-pin D-con- It runs PostScript and has no external human hand from start to finish. The as- nector to send and receive digital data controls — everything is controlled from sembly line is able to produce boards from the digital signal processor chip. the NeXT Computer. It doesn't need an much more quickly and accurately than The final connector is a 19-pin D-con- expensive PostScript interpreter and boards this complex have been nector for the monitor, which carries the controller inside it since the computer al- APC 100th Issue Page 39 BENCHTEST ready has the more advanced Display and the memory. Unfortunately, this isn't The ICP is optimised for these opera- PostScript. Instead, the computer does enough on a system designed for perfor- tions by including its own cache memory the imaging and the printer only has a mance on a network. There are too on-chip and by allowing it to make use of single VLSI custom chip inside. many I/O demands on the system; it burst modes in transferring data to and doesn't matter how fast the processor from main memory, as well as by allot- can run if it is constantly held up be- ting a memory buffer to each DMA chan- Inside the cube cause of competing access for memory nel. NeXT uses a 32-bit version of the NuBus and processor time from the network, The other custom VLSI chip is allotted architecture made popular by Apple in monitor, sound, printing, real time digital two DMA channels and it controls the the Mac II. The cube has four slots for signal processing and disk access. 256Mbyte optical disk, the SCSI connec- NuBus cards, with one holding the main The measure of performance that tor and the internal SCSI Winchester board. The board is extremely dense; it NeXT is using bases 75 per cent of sys- disk (if attached). This chip is known as is 30cm2 and holds all the circuitry to tem performance on data throughput the Optical Storage Processor and is re- control the computer and its peripherals. and 25 per cent on processor speed. quired because the optical drive is so The only non-CMOS component on this NeXT concentrated on system through- complex. The OSP includes error correc- board is a single array used for video put without compromising the basic tion code circuitry that ensures the data and Ethernet I/O. processor speed and claims an average on the optical disk is undamaged and it In the centre of the main board are the system throughput of 32Mbits per can correct read or write errors on the two custom VLSI chips that NeXT second, considerably better than com- fly. It operates its DMA channels simul- designed for the computer. These are parably priced workstations or personal taneously — one is used for reading the largest chips on the board, and both computers, and not much worse than a data off the drive or writing to it, and the are twice the size of the main processor. typical mainframe at 50Mbits per other for transmitting data from the OSP One chip, the Integrated Channel second. to processor or memory. Processor, is responsible for much of the The solution to throughput in the In one corner of the main board is the performance of the computer; a concept mainframe world has been to add a system RAM — 8Mbytes in sixteen taken from the mainframe environment. separate processor for every I/O channel 10Ons SIMMs of 500k each. RAM can The main bottleneck for microprocessor- to manage the flow of data between the be expanded on board to a maximum of based computers has been access to device and memory. NeXT uses the ICP 16Mbytes. The board also holds an addi- memory, and most microcomputer chip for this, which has 12 DMA chan- tional port, a 50-pin SCSI for the optional manufacturers have solved the problem nels that can be used to move data be- internal hard drives. These are by providing disk caches and processor tween an I/O device and memory without 330Mbyte and 660Mbyte full-size 5.25in caches to speed access between these interrupting the main 68030 processor. drives made by Maxtor. The NeXT Workspace: menus always pop onto the top of win- The Webster dictionary and thesaurus and the complete dows; the file browser includes filename filters; and windows works of Shakespeare on the CD can be accessed by any can be shunted off-screen application running on the workstation Also on the board is the main proces- early rumours, it was not manufactured laser is focused on the aluminum without sor, the 68030, clocked at 25MHz, and by Sony, but by Canon, which is not the magnetic field, which prevents the the 68882 numerical coprocessor renowned for its mass storage technol- alloy from melting or realigning incorrect- clocked at the same speed.