A review of the Hewlett-Packard Integral PC.
Published in Personal Computer World, June 1985

Hewlett-Packard Integral PC

Hewlett-Packard has attempted to build the ultimate portable - minicomputer specification and power in a compact, modern design.
Nick Walker takes a look at the single-user, Unix-based Integral PC
HP Integral in use

The Hewlett-Packard (HP) Integral Personal Computer has a specification that reads like a list of state-of-the-art micro-computer technology: 68000 processor with electroluminescent display; Think-Jet printer; 3½in micro-floppy disk drive; and the Unix operating system

I expected a large multi-user system with the traditional hefty Hewlett-Packard price tag. In fact, the machine is single-user and contained in one 25lb transportable box - the only thing I was right about was the price.


At 25 lbs and with physical dimensions similar to that of a sewing machine, the Integral is most definitely in the luggable category. It is smaller than other luggables, such as the Osborne, and fits comfortably on overhead shelves or under aircraft seats. When packed away the machine is encased in hard, grey plastic capable of taking the bumps and knocks of life on the road. HP went to some length to ensure the machine's durability, including dropping it from over three feet onto a solid floor.
HP Integral closed
The Integral PC is encased in extremely durable hard, grey plastic

To open the unit, slide two metal catches on the top outwards; the lid then slides back to reveal the printer. The keyboard detaches from the side, exposing the screen. You then plug in the keyboard at the front, mains power at the back and switch on. The first thing that strikes you is that the machine looks odd compared to other luggables. Due to the screen being so thin, the Integral can remain in its standing position (unlike other luggables that are tilted onto their side) so that it takes up considerably less desk space.

The Integral PC is based on a 16/32 bit 68000 micro-processor running at 8MHz, supplemented with a 16-bit custom graphics processor. Standard RAM is 512k made up of 256k by 1-bit DRAM chips with no parity chips. This is expandable to 1,5Mbytes internally, or 5Mbytes by means of an expansion card on one of the expansion ports. An extra 32k of RAM is reserved for the display and graphics processor, and hence is not seen by the user. The ROM is a massive 256k containing the Unix operating system, a window manager and a user-friendly interface.

Within the case is an almost silent fan. HP claims that the Integral will work in extreme conditions (that is 40 degrees C and 80 per cent humidity).

The real centrepiece of this machine is the electroluminescent display, which is as slim as an LCD but much clearer, faster and quite readable in direct sunlight. Such displays are not common as they are still an emerging technology and hence expensive, and, more importantly for portable manufacturers, really require mains power.

The integral can display a full-size 24 lines by 80 columns on its amber-only display. The screen itself measures 8 inches by 4 inches (twice the size of the Grid Compass display - the only other machine with the same screen technology) and when used graphically with its 512x255 bit-mapped pixels gives very high resolution. A number of fonts are provided for character displays, as well as a font editor to create your own. The viewing angle is adjusted by pulling the bottom of the display.

Only one true interface is available on the the back of the machine, the (Hewlett-Packard) standard IEEE-488 HP-1B interface bus. To this can be added standard HP peripherals such as plotters or other HP printers. In addition, this port is designed to accept a wide range of instrument controllers as used on HP scientific computers. A bus expander is available to hook up more instruments and peripherals. Further I/O capabilities such as RS232 communication are available with the purchase of an additional I/O board which plugs into one of the two expansion ports (also used for adding external memory). The two small British Telecom-style jack plugs on the front of the machine conform to HP's protocol for human input devices HP-HIL (Hewlett-Packard Human Interface Loop); the keyboard plugs into one, leaving the other free for mouse, touch tablet or any other HP-HIL device.
HP Integral back panel
The back of the machine supports just one true interface - the standard IEEE-488 HP-1B bus

The low-profile detachable keyboard is a full-size qwerty device with 90 keys including numeric keypad, eight function keys and numerous control keys. It has a good feel and a tilt mechanism at the rear to bring it to the right angle. The numeric keypad also has special functions which are accessed via the SHIFT key, such as delete line and insert character, and at its base are the cursor control keys. The Integral also has a SELECT key, used to select the active window for human interaction; an EXTENDED key for special characters; a PRINT key to dump any screen to the printer. The RESET/BREAK and STOP keys are in the top left-hand corner out of harm's way. The keyboard is completely soft-mappable, with the current definition of the function keys shown on the bottom lines of the display.
HP Integral keyboard
The low-profile detachable qwerty keyboard has 90 keys, a good feel and a tilt mechanism

Probably the biggest disappointment on a machine of this price is that HP has only included one disk drive. This is a 3½in micro-floppy drive to the right of the screen with disks inserted at 90 degrees to the normal. Although the lack of a second drive was somewhat compensated by the OS being entirely in ROM and the ability to define half of the available RAM as a RAM disk, I still missed a second drive. If the RAM was expanded to 1.5Mbytes and a reasonable amount set aside for a RAM disk, the loss wouldn't be as bad. The Integral takes hard-sectored, double-sided, double-density disks with a total storage capacity of 710k per disk. You can have more mass storage externally right up to a 55Mbyte hard disk drive.

The Integral has a built-in HP Think-Jet printer which uses a sack of ink squirted onto the paper in a controlled manner. HP also sells this printer as a peripheral with a Centronics interface to hook on to an IBM PC, BBC or any other machine with a Centronics port. Before using the printer for the first time time, you have to insert an ink sack complete with a strategically placed piece of blotting paper to catch the initial spurt of ink when the machine is switched on. The cartridge contains enough ink for 500 pages of text and the entire print head mechanism (a solid-state column of 12 individual squirters), so when you change the cartridge you also insert a new print head.

Although the printer will work with almost any paper, the mechanism is actually shooting droplets of ink at the paper, so very absorbent paper suffers from some fuzziness. HP supplies its own paper that works excellently. Two things about the paper loading annoyed me: firstly, a pile of paper behind the machine substantially increases the desk area used; and secondly, there is no platen knob so care is needed with the line-feed button.
HP Integral printer
Inside: The Think-Jet printer and electroluminescent display

In operation I was impressed by how quiet the printer was: there are no print head pins hitting the paper. It is also fast and flexible, printing at up to 150 characters a second in four different pitches. Graphics printing is supported, and any screen dumped will be printed accurately. The print quality falls between that of dot-matrix and daisy-wheel, and is certainly good enough for general letter-writing.

Electrical paths lead from each squirter to the front of the ink sack, where they meet with contacts on the carriage assembly. When the contact is activated, a small squirt of ink is projected from the ink sack to the paper.

The Think-Jet's four pitches are: normal 12 characters per inch (cpi) giving 80 characters per line; expanded six cpi giving 40 characters per line; compressed 21.3 cpi giving 142 characters per line; and 10.7 cpi giving 71 characters per line.

Each of these modes can be bold, underlined or both. Unlike dot-matrix printers that take multiple passes of the print head to print bold or underlined, the Think-Jet can do it in one, keeping its 150 characters per second print speed. You can also set the line spacing and the number of lines of text on each page.

A number of optional peripherals are available for the system including hard disks, laser printers, and plotters. The only optional peripheral with the review machine was the mouse, which I consider absolutely essential in order to use the windows and user-friendly interface. HP's mouse must rate as one of the most elegant designs with a circular hand grip and two buttons. The only problem with the mouse is that the BT socket is to the left of the machine; for right-handed use, a cable stretches across the keyboard.

System software

Two levels of system software are supplied with the Integral - the underlying Unix environment and, on top of this, HP's own user-friendly Personal Application Manager (PAM). Forematting [sic] the output from these and other applications is a program called HP Windows. All three are all in ROM, Including Unix.

The Unix supplied is an AT&T Bell Laboratories System III-compatible version called HP-UX 2.1, which is referred to in HP's literature as a 'vanilla' Unix environment. While the multi-user features of Unix are obviously lost on this machine, the multi-tasking features are not.

It is quite possible to be printing from one application while monitoring an instrument and updating a spreadsheet. I found no limit to the number of applications you can have running at one time, although the machine gets noticeably slower after about five or six. Even given all this, Unix does seem to be a case of overkill in a single-user micro. There is no way you can directly interact with the Unix ROM; to enter Unix commands, you need to run the HP-UX commands disk which gives you the 32 standard Unix commands including the Berkley enhancement 'csh', a Unix C Shell.

There are three other system software disks included: a utilities disk for performing standard system functions and system customisation; a diagnostic disk that tests all system components and reports any faults; and a system programming disk with the HP graphics language (HPGL), window and serial port drivers, and real-time extensions.

For users who use a mainframe system, the Integral can act as an intelligent terminal. You could then write source code on the mainframe, and download to the Integral to compile and run or vice versa. The Unix on the Integral is very flexible, as it can dynamically update itself through a RAM jump table. This gives the ability to emulate Xenix, System V and other Unix derivatives.

As a single user, it is rare that you will need to deal with Unix directly. All file manipulation and applications-running can be done from the Personal Application Manager (PAM), which is fundamentally the same front-end as found on the HP-150 but with some additions to incorporate the multi-tasking nature of the Integral and the operation within the window manager. The most significant advantage of PAM on the Integral over the HP is that all the software is in ROM, making it much faster and less cumbersome to use.

Upon the machine being switched on, PAM reads the disk drive, looks for installed applications and displays the names onscreen. The PAM window is divided into two sections. The upper portion, the command area, is where you issue commands and receive feedback from PAM. The lower portion, the folder area, displays the name of applications and data files. At the bottom of the screen is a user menu containing eight frequently-used file operations. Further system commands such as format are available on the system disk as PAM applications.

To run an application, you highlight the application name by mouse or by using the keyboard, and hit the function key corresponding to start (f1), again using either the mouse or the keyboard. A full description of PAM was featured in PCW's review of the HP-150 (May 1984), so I'll just concentrate on those features specific to the Integral.

PAM on the Integral supports pipelining: that is, two or more programs can be connected, whereby the output from one acts as the input to another while running concurrently. This means you could have program A obtaining data from the user, which would be passed via the first pipe to program B where it would be checked for validity. The validated data could then be passed by the second pipe to program C for formatting into a report. This would be specified to PAM as: program-A / program-B / program-C.

Similarly, there are times when it is necessary to specify purely sequential processing, such as making a back-up of a disk. A program can be set to run by itself only by adding a semicolon to the end of the program name: that is, backup 1;.

Also in ROM is HP Windows; a window, graphics, mouse and function key interface. Although not of the same quality as that of the Macintosh, Windows does provide a natural environment for multi-tasking. Windows allows you to place, stretch, hide and shuffle multiple windows, and is much easier to use when operating with a mouse. The top window is the only one with which you can interface directly. Each window is in fact treated as a separate 9600 baud terminal with 80 columns and 20 lines, and uses the normal control codes.

Applications software

A number of software packages are now available for the Integral. These include Microsoft's Multiplan, Ashton-Tate's dBaseIII, HP's own Memomaker and Visicorp's TK!Solver. On the software development front there are a number of Unix development tools, the C programming language and Basic.

The Basic is HP's technical Basic which is a version of ANSI Basic with extensions for maths, graphics and instrument I/O. Basic programs written on the HP 85/86 and on the series 200 and 500 machines will immediately run on the Integral. Applications written in C in a Unix environment can be down-loaded and compiled on the Integral. The C provided can access a Device Independent Library (DIL) for high-level control of instruments. And real-time extensions available through HP-UX provide interrupt-handling and priority setting for multi-tasking instrument control environments.

Benchmarks Hewlett Packard Integral PC
All timings in seconds. For a full listing of the Benchmark programs, see page 185, January Issue. [Or see my article.]
Machine loaned by Proteck.

More software is being developed, both by HP's own software division and by independent vendors. It is unlikely, however, that the machine will have as wide a range, or as competitive prices, as the IBM PC.

Six disks are bundled with the Integral: A tutor, a utilities disk, HP-UX commands, standard applications, diagnostics and a system disk. All except the standard applications are described in this review; standard applications furnishes you with two editors (font and text), three games and several alternative fonts.


The Integral PC is supplied with two A5 manuals - a user guide and a comprehensive guide - and a tutorial on disk.

Both manuals are clearly written and well indexed. The user guide is a step-by-step guide to using the Integral, the comprehensive guide gives more information on each aspect of the machine. I found that the comprehensive guide didn't go far enough in explaining the technicalities of the system, and should have been supplemented with a reference manual.

Beginners would be advised to forget the documentation and plug in the tutorial disk. This tutorial covers everything in the user guide and takes an estimated eight hours to fully absorb. It is broken up into eight lessons with each lesson subsequently broken into chapters; subjects include file organisation, use of windows, printing and creating files. Generally it's very well done, but it has a rather American 'Isn't this amazing' style. The Integral's documentation also includes a cartoon booklet showing you how to set up and start, and also how to pack the machine away for transportation.


The Integral Personal Computer follows HP's tradition of high quality and high price it costs £5450. The optional mouse costs £152, and the Think-Jet printer on its own costs £550 with an HP interface or a Centronics interface.


I started this Benchtest with considerable doubts about the viability of a machine that uses Unix in ROM and which is designed purely for a single user. However, HP has created a machine that makes an awful lot of computer power easy to use. The windowing software makes multi-tasking a natural activity with no worries about task priorities, foreground/background tasks and scheduling. One week of using this machine and then returning to MS-DOS on an IBM PC really made me realise the power of UNIX

As for the possible market for the machine, it is hard to tell who will buy it. Certainly, computer scientists who use Unix now will appreciate the benefit of a complete, luggable Unix system. Similarly, scientists using HP's existing scientific computers will find it a logical upgrade. The multi-tasking facilities may well draw other users who have outgrown operating systems such as MS-DOS.

From the nature of the manuals and software developed, it is obvious that HP also sees the machine selling to business and first-time users. But with its high price and limited and expensive software, I don't forsee [sic] many sales in this area. It may sell to those who want to find a way of switching to Unix at a reasonable price, or those who purely want to cast a vote against the IBM PC.

If nothing else, the Integral PC must be admired for its all-in-one-box approach, the state-of-the-art technology, easy-to-use multi-tasking, high build quality, and the ingenuity that went into making Unix a ROM-based operating system.       END

Technical specifications
 Processor:8MHz 68000 supplemented with 16-bit graphics processor
 RAM:512k (additional 32k for graphics)
 Mass storage:One 3½in 710k micro-floppy
 Keyboard:90 keys, numeric keypad and eight function keys
 Size:8½ins X 13ins X 17ins
 I/O:HP interface bus (HP-1B, IEEE-488), two expansion ports, two human interface loops (HP-HIL)
Personal Application Manager (PAM) and HP Windows in ROM. Six disks containing Tutor, Utilities, HP-UX commands, Standard Applications, Diagnostic, System commands.
 Peripherals:Built-in Think-Jet printer.
 Options:RAM expandable to 1.5Mbytes internally, 5Mbyte externally. Hard disks, printers, plotters and I/O cards.

In perspective
There is little or no direct competition for the HP Integral PC. If it is purely considered as a single-disk transportable system, there is no doubt that it is very expensive, but that is comparing it with an MS-DOS transportable such as the Apricot or Compaq. If a Unix machine is what you are looking for, then this may well be the cheapest way of getting one with the added advantage of portability, although higher-priced Unix machines will be multi-user and higher performance.
As for its viability as a business transportable or professional beginner's machine, there are a number of IBM PC compatibles and MS-DOS transportables with a wealth of business software and a considerably lower price tag. Beginners looking for a particularly friendly business machine would do better with the Apple Macintosh, although the Integral is the friendliest way I've seen to introduce multi-tasking.
Where the Integral is really on its own is as a transportable for computer scientists and software engineers who work on a Unix mainframe, who could use it as a terminal at work and to develop software at home. Scientists planning to use its instrument control features would be well advised to look at the [sic] HP's lesser machines such as the HP-85 or 86 before paying extra for the Integral. But having said that, the Integral would be capable of monitoring far more complex experiments due to its multi-tasking nature.


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