hp-series300.netHP 9000 series 300 vintage computers


The HP300 series introduced a modular architecture based on a system processor unit (SPU) containing little more than cooling fans and a passive motherboard providing power, address and data buses for a set of plug-in card slots. All the active elements of the computer (including CPU, memory, graphics system and interfaces) were implemented on one or more plug-in boards; the power supply was also a plug-in module. A basic system was completed with an HP-HIL keyboard (and optionally an HP-HIL mouse), a suitable monitor, and a supported disc drive. On-board memory ranged from 1 Mbyte in the 310 base model to a maximum of 128 Mbyte in the 380. All models utilized 32-bit Motorola MC680X0 CPUs ranging from the MC68010 through to the MC68040; see our series 300 hardware fact file for the specifications of each model in the range. HP marketed a full-range of peripheral devices and offered limited support for some third-party hardware. Additional information on 300-series hardware can be found at the HP Computer Museum and in the Bitsavers Document Archive.


1. The Standard Form Factor

The HP300 series launched with the models 310 and 320. The entry-level 310 was based on a MC68010 processor running at 10 MHz with 1 Mbyte of memory, interfaces and monochrome graphics all integrated on a single processor board. The 320 boasted a more advanced MC68020 CPU running at 16.7 MHz and was implemented on three separate boards: processor, interfaces and graphics. The same standard form factor, known as the Integrated Terminal Format or ITF, was used by ten of the series 300 computers (130 mm height x 325 mm width x 376 mm depth), albeit with different adaptations of the digital I/O slots.

Model 310 rear view
HP310 rear panel showing SPU board and colour frame buffer graphics board.
Photo credit: Thomas Schanz (Wikimedia Commons)

Although introduced later in the series lifetime (in 1989), the the model 332 had much in common with the 310. It was the lowest cost MC68030 machine and, like the 310, was implemented on a single board. Models 310 and 332 were primarily aimed at instrument/process control applications running under BASIC/WS. Neither came with dedicated floating-point hardware, although both could be upgraded: the 310 by means of a plug-in board and the 332 by inserting a MC68882 floating point unit (FPU) in the empty socket on the processor board. Both models were also available without integrated graphics, allowing a separate frame buffer board to provide higher-performance monochrome or colour graphics. The model 332 ran some four times faster than the 310 and could be fitted with up to 8 Mbytes of RAM.

Models 330 and 350 joined the series in 1987. Like the 320, these machines utilized the MC68020 CPU (with a MC68881 FPU) and featured separate processor, interface and video boards, leaving one full height I/O slot. The 330 ran at 16.7 MHz and the 350 at 25 MHz. These were true 32-bit computers with 32-bit internal architecture, 32-bit addressing and the capability to do 32-bit digital I/O via the new DIO-II bus. Models 360 and 370 moved up to the MC68030 CPU, with the MC68882 FPU, and were introduced the following year. These machines put the RAM on an additional board linked directly to the processor board via a dedicated system bus integrated into the rear panel, leaving no free slots. Models 330, 350, 360 and 370 were promoted primarily as HP-UX workstations and had maximum memory configurations ranging from 8 Mbytes on the 330 to 48 Mbytes on the 370.

Model 375 rear view
HP375 rear view showing SPU with PSU partially removed and bus expander unit on top.
Photo credit: Thomas Schanz (Wikimedia Commons)

The remaining models in the standard form factor (375, 380 and 385) used a double-height processor board so that, with a separate video board, one free full height I/O slot was available. Models 380 and 385 used identical processor boards and operated with MC68040 processors. However, as release of the MC68040 CPU was delayed by technical difficulties at Motorola, the model 375 was released ahead of the 380. This also used the same processor board as the 380 but had a 50 MHz MC68030/MC68882 daughter board to emulate the functions of the MC68040. This large 'L'-shaped board plugged into the MC68040 socket and HP offered a processor swap to upgrade the 375 to 380 specification once the MC68040 was available in quantity. The model 380 used a 25 MHz MC68040 but the processor board could also operate with a 33 MHz MC68040, making a model 385; however, this top-of-the-line specification does not seem to have been actively marketed.

Model 375 processor board
HP375 processor board with daughter boards and four RAM cards.
Photo credit: Thomas Schanz (Wikimedia Commons)
Model 380 rear panel
HP380 processor board rear panel.


Digital I/O Hardware

Seen from the rear, the standard form factor SPU provided four full-height slots (30 mm high) to accommodate processor, graphics, interface and other boards. Depending on the motherboard and the type of card cage fitted, each of these slots could accommodate either one full-width board (210 mm wide x 290 mm deep), or up to two narrower boards (170 mm wide x 137 mm deep) conforming to the 16-bit DIO-I standard inherited from HP 9000 series 200 computers. In this way, DIO-I slots always came in pairs, one pair for each full-height slot. However, DIO-I interface cards were fitted with a full-height faceplate to accommodate the interface connectors. Therefore only every other DIO-I slot could accommodate an interface card, while the intermediate slots could accommodate, for example, memory or ROM boards with no faceplate. While the full-width boards could also interface to the 16-bit DIO-I bus, many implemented the newer 32-bit DIO-II standard. Processor and graphics boards were always of the full-width type.

Models 310, 320 and 332 used only the 16-bit DIO-I system. The processor board, separate human interface board (model 320) and any graphics board were located in full-width 16-bit 'system' slots. The remaining one or two full-height slots were fitted with a card cage to provide two or four DIO-I card slots.

Starting with the model 330, the motherboard in the SPU was updated to provide four identical DIO-II card slots. Any spare DIO-II slot could be adapted to provide a pair of DIO-I slots by means of a card cage. The new motherboard retained the original 96-pin DIO-I connector but added a new 48-pin connector providing the additional address and data lines required for 32-bit operation. All standard form factor SPUs could be coupled with bus expander units to provide additional DIO-I or DIO-II slots. The bus data rate was 3 Mbytes/s for DIO-I. Since the DIO-II interface ran at the same clock speed as DIO-I, but was 32-bits wide instead of 16, it ran at 6 Mbytes/s.

ITF System Units
System Unit I/O configurations. Top: 2 x DOI-II + 4 x DIO-I. Bottom: 4 x DIO-II.
Photo credit: Thomas Schanz (Wikimedia Commons)


Other Form Factors

Desktop Systems

Other models in the series used alternative form factors (designated here as 'short', 'long' or 'wide') that provided either zero or one DIO expansion slots. The short and long form factors were used for lower-cost workstation bundles with no or limited scope for expansion. Models 318M and 319C+ were implemented in the 'short' form factor (100 mm height x 325 mm width x 325 mm depth) with no free I/O slots. Both were based on the model 330 processor board with MC68020 CPU and MC68881 FPU running at 16.7 MHz. The 318M had 4 Mbytes of RAM and high-resolution monochrome graphics, while the 319C+ had 4 to 16 Mbytes of RAM and high-resolution colour graphics.

Model 340 used the 'long' form factor (100 mm height x 325 mm width x 444 mm depth) and had a MC68030 CPU and MC68882 FPU running at 16.7 MHz. Originally announced in the 1989 HP Catalogue as the 'Model 349', this entry-level machine was available with a choice of monochrome or colour high-resolution graphics, including an optional 3D graphics display controller. RAM ranged from 4 to 16 Mbytes and there was an optional DIO-I expansion slot. The model 345 had the same form factor but used a processor board similar to the that in the model 375 with a 50 MHz MC68030 and 50 MHz MC68882 FPU on a daughter board emulating the MC68040. The model 345 was also the first 300-series computer to offer an internal disc drive: a 200 Mbyte SCSI hard drive.

Models 362 and 382 (and the rack-mount variants 362/R and 382/R) were the last models in the 300 series to be actively marketed. They introduced a new 'wide' form factor (89 mm height x 419 mm width x 432 mm depth) designed to accommodate up to two internal drives: a hard disk and either a 3.5" floppy drive or a CD-ROM drive. The model 362, aimed primarily at instrument/process control applications running under BASIC/WS, featured a 25 MHz MC68030 CPU with MC68882 FPU, 2 to 16 Mbytes RAM, integrated VGA-resolution colour graphics and up to two internal drives. Model 382 was a more powerful HP-UX workstation: 25 MHz MC68040, 8 to 32 Mbytes RAM, VGA or high-resolution colour graphics and up to two internal drives. Both wide models had a single DIO-I card slot but could be coupled with up to two bus expanders, each providing either two DIO-II slots or four DIO-I slots.

Rack-Mount Systems

Three fully-integrated rack-mount variants (models R/332, R/362 and R/382) were developed featuring built-in 9" monitor with optional touch-screen functionality, detachable keyboard and two internal disc drives (one hard, one 3.5" floppy). These rugged machines matched their desktop counterparts in terms of processor and memory specifications and were aimed at instrument and process control applications running under BASIC/WS or (on the R/382) HP-UX with BASIC/UX. Kits were also available to mount both standard-form-factor and wide-form-factor SPUs and a monitor in a standard 17" instrument rack; however, at just 7" high (4U), the integrated rack-mount units used much less rack space. HP also manufactured elegant cabinets to accommodate standard-form-factor SPUs, disc drives and other series 300 units.

ITF System Units
R/382 Rack-Mount Instrument Controller.
Photo credit: (HP Computer Museum)

Yet another variant of the 300 series were the model V/360 and V/382 VXI embedded controllers which were designed to be plugged into a VXI mainframe and to function as the slot-0 VXI system controller. The V-series controllers had similar hardware specifications to the corresponding desktop model (except for an absence of internal drives). VXI software drivers for BASIC/WS were available.


Bus Expanders

HP provided a range of standard-form-factor bus expanders providing 0, 2, 3 or 4 DIO-II slots combined with 8, 4, 2 and 0 DIO-I slots, respectively. These bus expanders were stacked on top of the SPU and connected directly to the backplane by means of ribbon cables that passed through slots in the lid of the SPU and the base of the expander. Generally, up to two bus expanders could be added, except on the models 310, 320 and 332 which were limited to a single 8-slot DIO-I expander. The model 9888A 16-slot DIO-I expander could also be used with any series 300 computer having a spare DIO-I slot.

Another standard-form-factor bus expander (HP98577A) was available to provide VMEbus capabilities. This unit was equipped with four industry-standard VMEbus card slots plus a fifth slot reserved for a VMEbus controller card. This expander also connected directly to the SPU backplane via ribbon cables

With the introduction of models 362 and 382, new wide-form-factor bus expanders were added providing 0, 1 or 2 DIO-II slots in combination with 4, 2 or 0 DIO-I slots, respectively.


Coprocessor Cards

By the mid-1980s, IBM PC-compatible machines already dominated the personal computer market. Series 300 machines were of course not compatible but HP offered two complementary options for coexistence. The first was the 'DOS Coprocessor Card' (HP98286A) which was a DIO-I card fitted with an Intel 80286 CPU and 80287 FPU. This computer-within-a-computer could be run as an application under an HP-UX Application eXecution Environment (AXE) and allowed most DOS-based software to be used on HP300 machines. An IBM-compatible 5.25" flexible disc drive (HP 9127A) was required.

Conversely, HP's Basic Language Measurement Coprocessors, codenamed Viper, were PC-compatible ISA cards providing elements of series 200/300 hardware and software inside a PC. The HP82300 Viper card, launched in 1987, had a MC68000 CPU running at 8 MHz with 0.5 Mbytes of RAM and BASIC/WS 5.0 in ROM. It also provided the HP-IB interface needed in many instrument control applications. Although slower than any series 300 machine, these cards were quite successful and an updated model, the HP82321, was launched in 1992; this featured a 16.7 MHz MC68030 CPU and had specifications matching the model 332.


System Performance

HP liked to measure processor speed in MIPS (millions of instructions per second) and, as shown below, performance measured by that metric improved dramatically across the 300 series. RAM speed was also greatly improved, read cycle times falling from over 500 ns on the model 320 to 40 ns on the 380. Except for some of the early models which used the DIO bus for memory access, a dedicated memory bus allowed the RAM to run synchronously with the processor.

Series 300 processor speeds
HP300 series processor performance expressed in MIPS (note the logarithmic vertical axis).

Floating-point performance was not usually specified but mid-range machines benchmarked at between 0.1 (model 330) and 0.6 (model 370 with floating-point accelerator) Mflop (1 Mflop = 1 million double-precision floating-point operations per second). The models 380 and 382 reached 2.2 Mflop and the 385 about 2.9 Mflop. This was substantially better than contemporary PCs but well behind the PA-RISC-based series 700 workstations then launching with floating-point speeds upwards of 10 Mflop.


Graphics Systems

HP competed strongly in the area of graphics performance, developing a range of advanced monochrome and colour graphics boards based on proprietary frame-buffer integrated circuits, as well as external graphics display stations with hardware acceleration for 2D and 3D animation and 3D solid rendering.

Graphics Boards and Monitors

The graphics boards or 'frame buffers' occupied a system slot in the computer case and used either the DIO-I or DIO-II bus. They connected to the monitor via one (monochrome) or three (RGB colour) coaxial cables implementing a composite video signal including synchronization pulses. For colour systems, this is also known as 'sync on green'. Pixel resolution was up to 1280 x 1024 with up to 8-bit colour depth coupled with a 24-bit colour map. The vertical refresh rate (VRR) was generally 60 Hz (but 72 Hz for the A1096A), while the horizontal scan rate (HSR) varied with resolution from 25.5 kHz for 512 x 400 resolution to 63.3 kHz for 1280 x 1024 resolution.

Series 300 Graphics Boards

Model Type Resolution VRR (Hz) HSR (kHz) HP Monitors IC codename
98542A Mono 512 x 400 60 25.5 35731A 12"
98543A 16 colours 512 x 400 60 25.5 35741A 12" Topcat
98544B Mono 1024 x 768 60 47.7 98786A 17"
98788A 19"
98545A 16 colours 1024 x 768 60 47.7 98785A 16"
98751A 19"
98547A 64 colours 1024 x 768 60 47.7 98785A 16"
98751A 19"
98548A Mono 1280 x 1024 60 63.3 98788A 19" Catseye
98549A 64 colours 1024 x 768 60 63.3 98751A 19" Catseye *
98550A 256 colours 1280 x 1024 60 63.3 98789A 16"
98752A 19"
98754A 19"
Catseye *†
A1096A Mono 1280 x 1024 72 63.3 98774A 19" Hyperion ‡
A1416A 256 colours 1280 x 1024 60 63.3 98789A 16"
98754A 19"
A1097A 19"
Kathmandu †

* Optional model 98556A 2D graphics accelerator daughter board available. † 8-bits per pixel plus two overlay planes (accessible from HP-UX Starbase software). ‡ Not fully supported under HP operating systems.

Series 300 graphics boards
HP300 series medium- and high-resolution colour graphics boards (Left: 98547A Topcat. Right: 98550A Catseye).
Photo credit: Thomas Schanz (Wikimedia Commons & Wikimedia Commons)

Two or more graphics boards could be used in systems with a sufficient number of DIO-II slots. In this way, multiple displays were supported under HP-UX running X Windows or HP VUE. However, all these graphics boards (except for the 98550A with 98556A daughter board) were essentially simple frame buffers that left most of the work of image manipulation to the CPU.

HP monitors used Sony-manufactured CRTs and the table above list the monitors paired with the different graphics boards. Multi-sync colour monitors supporting multiple refresh and scan rates, such as the D1187A (20") and the D1188A (16"), were also offered with later series 300 computers.

HP 35731A 12
HP 35731A 12" monochrome monitor

Graphics Display Stations

A range of graphics display stations, incorporating their own graphics processor unit (GPU), was available. These used a rather brute-force approach to obtain high resolution, extended colour depth and accelerated image manipulation sufficient for real-time animation. They were heavy and power-hungry external units, in standard-form-factor cases, connected to the SPU via a DIO-I or DIO-II interface card. Each graphics display station could accommodated multiple frame-buffer cards providing between 4 and 32 bits per pixel, with the fully-loaded version permitting 24-bit true colour plus overlay planes. The entry-level model 98700A Display Controller, coupled with the 98710A Graphics Accelerator, was known as the Gatorbox and provided 1280 x 1024 resolution with either 16 or 256 colours (4 or 8 bits per pixel). The mid-range 98720A SRX 3D Display Controller and 98721A 3D Solid Rendering Graphics Accelerator, together codenamed Renaissance SRX, provided 1280 x 1024 resolution with up to 24 bits per pixel for true colour rendition. Top of the range in 1988 was the 98730A TurboSRX 3D Display Controller with the 98732A 3D Solid Rendering Graphics Accelerator (DaVinci TurboSRX) providing 1280 x 1024 resolution 24-bit colour and z-buffering hardware acceleration for a price in excess of $50,000. 1990 saw the introduction of a family of single-box graphics display stations, the models 98705A/B/C Tigershark TurboVRX , which were aimed especially at animated 3D wire-frame and solid-rendering graphics. The Tigershark was a another standard-form-factor unit that connected to a series 300 or 400 computer via an DIO-II interface card. These display stations were also used with series 700 computers but with a different front grill and interface card.

Bundled Systems

HP's configurable 300-series computers were available in bundled packages with SPU, graphics system and HIL accessories included. The bundles were designated by the model number and the graphics option: medium-resolution monochrome (M), 1024 x 768 resolution monochrome (MH), 1024 x 768 resolution colour (C+), accelerated high-resolution colour (CHX), entry-level 3D (SRX) and high-performance 3D (TurboSRX).


Interfaces and Peripherals


Every HP300 series computer came with built-in RS232 and HP-IB interfaces. The RS232 provided serial communications with terminals and other computers, while the HP-IB permitted connection to mass-storage units, I/O devices and many HP instruments. The HP-IB interface developed by HP provided (for the time) high-speed parallel data transfer and was latter adopted as the IEEE 488 interface standard. The HP-IB could, in principle, connect up to 32 devices simultaneously and offered data transfer rates of up to 360 kbytes per second. Practical data rates with the standard HP-IB interface were limited by the slowest responding device on the bus. To addresses this issues, a higher-speed HP-IB interface (HP-IB disc) was introduced which could operate at transfer rates up to 2 Mbyte/s and was usually dedicated to disc units. Later models in the series came with a LAN interface as standard and several provided a 50-pin 8-bit SCSI-I interface enabling a wide range of multi-vendor disc, tape and CD ROM drives to be used, including some later SCSI-II devices. DIO cards were available to add additional interfaces including SCSI, serial, DataComm, LAN, BCD, GPIO and SRM interfaces. HP used their proprietary HP-HIL interface for connecting keyboards, mice and several other human I/O devices.

Shared Resources Management and Network Hardware

The technology for computer clusters and networks developed rapidly during the lifetime of the series 300. Initially, the emphasis was on sharing expensive hard-drive and printer/plotter facilities between a small local cluster of workstations. For this purpose, HP developed their proprietary Shared Resources Management (SRM) network system based on series-200 technology. An SRM cluster comprised a dedicated server, to which shared disc drives, printers and plotters were connected, and a cluster of clients which could include series 200, 300 and 500 workstations, each running any of the supported operating systems. Early SRM systems used a model 220 or 236 workstation as the server; later a dedicated SRM server, model 50960A, was launched. The server was dedicated to SRM operations and could not be used as a regular workstation. Early cabling was a radial multi-core system but this was replaced by a daisy-chained RG 58C/U coaxial system operating at 0.9 Mbit/s. SRM was a complete resource sharing system for small clusters but provided no external communications. With the introduction of SRM/UX software in 1990, SRM services could be provided over the LAN from an HP-UX cluster server without requring any special SRM hardware.

Series 300 ethernet connectors
HP300 series AUI LAN connector with 10-base-T MAU and RJ-45 cable connected. An unused BNC coaxial LAN connector can also be seen on the left.

With the 300 series, HP gradually moved away from the proprietary SRM towards a more open LAN system based on emerging ethernet standards. Models with built-in LAN provided a 10-base-2 'thinLAN' coaxial connector similar to the SRM system and popular with other vendors at that time. Later models also provided an Attachment Unit Interface (AUI) in the form of a 15-pin connector to which a small external Media Attachment Unit (MAU), or transceiver, was connected as a physical interface to different types of IEEE 802.3 standard networks. Transceivers were available for 10-base-T ethernet (RJ-45 port), 10-Base-2 (BNC port) and fibre-optic (ST port) cables. Jumpers on the processor board were used to select between the thinLAN and AUI interface connectors. Both operated at up to 10 Mbits/s. The 10-base-T system is compatible with modern LAN systems, provided they can operate at that (now slow) data rate.

Printers and Plotters

HP offered an extensive range of printers and pen plotters, with most early models communicating over the HP-IB interface. Later computers in the 300 series included a parallel printer interface and even allowed network printing with HP's JetDirect protocol. One of the most innovative printers of the era was HP's Thinkjet, the first commercial inkjet printer introduced in 1984. This small, quiet and comparatively cheap printer was ideal for routine work, although it did require special fan-fold paper and there was no cut-sheet feeder. The later deskjet (1987) was faster, used plain cut-sheet paper and produced high-resolution (300 dpi) output. Laser printer technology was also contemporary with the 300 series (the first Laserjet printer having been launched in 1984) and HP were the market leaders.

With HP's strong presence in the CAD/CAM market, a wide range of flat-bed and roll-feed pen plotters was developed. The former are exemplifier by the 7475A flat-bed plotter which had six pens and could operate with both A/A4 and B/A3 size media. For large format work, roll-feed plotters, such as the top-of-the-range DraftMaster, were used. The DraftMaster could plot on cut sheets up to size E/A0 or on continuous roll media up to 919 mm wide. Available media included matt and glossy paper, polyester drafting film and transparency film.

The HP Computer Museum has extensive information on all contemporary HP printers and plotters.

Human Interface Devices

As already mentioned, HP developed a special system for the 'human interface'. In addition to keyboards and mice, the HP-HIL interface also supported a graphical input tablet, rotary encoders and multi-button selection boxes which could be accessed from user-developed BASIC or Pascal software. Again, the HP Computer Museum has details.


Mass Storage

The majority of HP300 computers had no built-in mass storage device. Over the evolution of the 300 series, mass storage options expanded greatly in terms of speed and capacity. On the early machines, the built-in HP-IB interface was used to communicate with disc drives, which ranged from 270 Kbyte capacity single-sided 3.5” diskettes to hard drives with capacities of a few tens of Mbytes. At maturity, HP-IB and SCSI hard drives with capacities of up to 2 Gbytes were supported. Cartridge tapes were the preferred media for system backups and for installation of large software distributions on HP-UX machines (until replaced by CD-ROMs and DDS), while flexible discs were generally used for distribution and backup of non-HP-UX software and data. Physically, most of the mass storage units were the same width as series 300 computers and were stackable with them; many also used the same height and front grill design.

With early HP-IB drives, a language called Amigo was used to exchange commands and data between the computer and the drive. Subsequently, HP developed 'Command Set for the 1980s' (CS/80) and a reduced instruction set called 'Subset 80' (SS/80) which was used with flexible disc drives.

Flexible Discs and Drives

The 3.5" flexible disc format was generally used, although a 5.25" drive was also available for use with the DOS co-processor and earlier 5.25" Amigo drives could be used. 3.5" flexible discs came in different specifications: single sided (SS) or double sided (DS); double density (DD) or high density (HD). HP supplied its own brand of 3.5" flexible discs which were colour coded: blue for SS/DD; grey for DS/DD; black for DS/HD. The DS/HD discs are distinguished by a rectangular hole near the bottom right hand corner and are not recommended for use in DD drives*. Several different formatting options were available for each type of disc according to the number of bytes per sector and the number of tracks per side. HP generally used 77 tracks per side on DS/DD and DS/HD media, with 3 spares, rather than the more common 80 tracks. DS/DD media could provided up to 770 Kbyte capacity in HP drives and DS/HD discs up to 1540 Kbytes. Unfortunately, flexible discs written on HP drives were mostly incompatible with other computer systems: firstly because the de facto standard formats with 512 bytes sectors and 80 tracks per side were not supported on most series-300 systems; and secondly because the LIF filing system could not normally be read by other operating systems. HP did provide software (LIF UTILS) to allow some (but not all) IBM-compatible PCs to read and write LIF-format flexible discs. The later HP flexible disc drive in the 9153C combo unit supported DS/HD discs formatted with 512 bytes per sector and 80 tracks, making them 'IBM-compatible' under HP-UX 9.x and BASIC/WS 6.x with the optional 'DOS filing system' software. HP flexible disc drives used a feature called Media Monitor to measure the usage of a given disc and to indicate, by permanently illuminating the activity disc light, when a disc should be considered worn out. Continued use of the disc would result in it being automatically marked as read only. The table below summarises the different 3.5" flexible disc format supported on contemporary HP hardware.

* By covering the hole in the bottom right hand corner, an HD disc can be used in a DD drive but reliability is impaired.

3.5" Flexible Disc Format Options

Bytes/sector 256 256 512 512 1024 256 512 512 1024
Sectors/track 16 16 9 9 5 32 18 18 10
Tracks 66 77 77 80 77 77 77 80 77
Capacity (Kbytes) 264 616 693 720 770 1232 1386 1440 1540
HP format option 4 0, 1 2 16 3 1, 2, 4 2 16 3

Note: 1 Kbyte = 1024 bytes.

The table below details the flexible disc drives most commonly paired with series 300 computers together with their maximum formatted storage capacity. All used the HP-IB interface and SS/80 protocols.

HP-IB Flexible Disc Drives

Model Single/Dual Disc Maximum capacity (Kbytes)* Command set
9121S single 3.5" SS/DD 264 Amigo
9121D dual 3.5" SS/DD 264 Amigo
9122S single 3.5" DS/DD 770 SS/80
9122D dual 3.5" DS/DD 770 SS/80
9122C dual 3.5" DS/HD 1540 SS/80
9127A single 5.25" DS 770 SS/80

*Disc capacity depends upon the sector size used. Note: 1 Kbyte = 1024 bytes.

Combo Drives

For many applications, the perfect mass-storage option was a combo drive containing a hard disc and either a 3.5" flexible disc drive or a 1/4" cartridge-tape drive. Combo units had a single HP-IB address but used secondary addressing to communicate with the individual drives within the unit. The combo units used the same discs and tapes as their stand-alone equivalents. The table below details the combo units commonly paired with series 300 computers.

HP-IB Combo Drives (all CS/80)

Model Removable medium Removable medium type Hard drive formatted capacity (Mbytes)
9133D 3.5" disc DS/DD 14.8*
9133H 3.5" disc DS/DD 19.9*
9133L 3.5" disc DS/DD 39.9*
9153A 3.5" disc DS/DD 10
9153B 3.5" disc DS/DD 20
9153C 3.5" disc DS/HD 10, 20 or 40
7908 1/4" tape 88140 16.6
7911 1/4" tape 88140 28.1
7912 1/4" tape 88140 65.6
7914 1/4" tape 88140 132
7914CT 1/4" tape 92245 132
7942A 1/4" tape 92245 23.8
7946A 1/4" tape 92245 55.5

* Drive capacity based on 256 byte sectors (12% uplift if formatted with 1024 byte sectors). Note: 1 Mbyte = 1024 Kbytes = 1,048,576 bytes.

Hard Drives

Stand-alone HP-IB hard drive units were available with storage capacities from about 24 Mbytes to 671 Mbytes. These were normally coupled with a high-speed HP-IB interface in the computer to avoid communication being slowed by other devices present on the regular HP-IB interface. Following the introduction of the SCSI interface, further improvements in hard-drive speed and capacity were possible and, by the end of the 300-series lifetime, 2 Gbyte SCSI drives were supported. The 8-bit SCSI-I protocol was used with 50-pin connectors. Since the SCSI-I protocol is a subset of the later SCSI-II, drives of the latter type (including third-party drives) with the 50-pin interface may work with series 300 computers. Because of the limits of 32-bit addressing, the largest formatted capacity possible is 4 Gbytes - 1 Kbyte or, if the drive is to be bootable, exactly 2 Gbytes. The tables below detail the HP-IB and SCSI hard drives onto which HP-UX 9.x will install.

HP-IB Hard Drives (all CS/80)

Model Formatted capacity (Mbytes) Model Formatted capacity (Mbytes)
7933H 404 7935H 404*
7936H 308 7937H 571
7941A 23.8 7945A 55.5
7957A 81.7 7958A 131
7957B 81.7 7958B 152
7959B 304 9134L 39.9**
C2200A 335 C2203A 671

* Removable media. ** Drive capacity based on 256 byte sectors (12% uplift if formatted with 1024 byte sectors). Note: 1 Mbyte = 1024 Kbytes = 1,048,576 bytes.

SCSI Hard Drives (HP and third party)

Supplier Model Formatted capacity (Mbytes) Supplier Model Formatted capacity (Mbytes)
HP 7937S 571 Rodime RO3000T 200
HP 7957S 108 Quantum PD210S 200
HP 7958S 162 Quantum PD425S 4030
HP 7959S 323 Quantum LPS5250S 500
HP 2212A 199 Quantum PD1050S 1001
HP 2213A 331 Micropolis 1588 363
HP C2233 199 Micropolis 1528 1280
HP C2235 403 Micropolis 1924 1860
HP C2247 1001 Segate ST3600N 5000
HP C3010 1860 HP 79560 1250

Note: 1 Mbyte = 1024 Kbytes = 1,048,576 bytes.

Tape Drives

Two single-unit tape drives were available using specially-formatted 1/4" DC-600 cartridge tapes in lengths of either 150' or 600'. The HP 9144A drive used a 16-track format with capacities of 16 Mbytes (150' tape) or 67 Mbyte (600' tape), while the HP 9145A used 32 tracks with capacities of 32 Mbytes or 133 Mbyte. 'DC-600' only designates the mechanical form factor and not the data-storage format. Tapes for use in HP drives were factory pre-formatted for life according to a 3M standard (either HCD-75 or HCD-134) and, while they could be re-written, the hardware provided no re-formatting capability. HP-branded tapes were product numbers 88140SC (16 Mb) and 88140LC (67 Mb) for the 9144A, and 92245S (32 Mb) and 92245L (133 Mb) for the 9145A. Compatible tapes made by 3M/Imation were DC600HC and DC615HC (16 track, 3M format HCD-75) and DC600XTD and DC615XTD (32 track, 3M format HCD-134). The 9145A was backwards compatible to the extent that it could read (but not write) 16-track tapes. Although physically identical, QIC cartridge tapes do not work in HP drives. The entire system is of course now obsolete. Furthermore, the tapes used an elastic tensioning band within the cartridge that stretches over time. For this reason, original tapes are most likely unusable without changing or reconditioning this band, as described on the HP Computer Museum website.

The 9144A and 9145A tape drives used the CS/80 communication protocol over the HP-IB interface and were capable of random access, albeit very slowly. The average seek time on a 150' tape was 2 minutes. The drives also had quite sophisticated error checking with both read-while-write checking and an error checking and correcting (ECC) algorithm. Additionally, tapes were checked by the machine when loaded and bad blocks could be identified and spared. Finally, the drive maintained a count of write passes, stored in the tape header, and automatically designates a tape as read only after a certain number.

In 1989, the Digital Data Storage (DDS) standard was introduced, based on the 4 mm Digital Audio Tape (DAT) format, providing in the first generation (DDS-I) uncompressed storage capacity of 1.3 Gbytes (60 m tape) or 2 Gbytes (90 m tape). Supported HP DDS-I tape drives with SCSI-I interfaces were models C1511A and C1512A (for 60 m DDS-I tapes) and model C1520B (for either 60 m or 90 m tapes DDS-I tapes). The DDS-II standard, introduced in 1993, uses a longer tape (120 m) and a finer track pitch to provide 4 Gbytes uncompressed capacity. The DDS-II format appears to be unsupported on series 300 computers but may nevertheless function correctly; however, compatibility with tapes written on a DDS-I drive is not guaranteed.

Optical Drives

HP introduced its first CD-ROM drives for 9000 series computers in 1990. The model 600/A used the HP-IB interface and could read disc written in the 600 Mbyte ISO 9660:1988 level 2 'High Sierra' format. By 1992, SCSI CD-ROM drives (e.g. models A1999A) were available, including an internal CD-ROM drive for the models 362 and 382. CD-RW technology was introduced with the model 650/A magneto-optical drive, allowing both software install and backups with one fast and robust device. Most SCSI-II CD-ROM drives will work with series-300 computers provided they operate with 512 (rather than the now standard 2048) bytes per sector. HP CD-ROM drives from the 1990s often had jumpers to select between 512 and 2048 bytes per sector.