High-performance designs for the low-cost PA-RISC desktop - processor, memory, graphics, multimedia and built-in core I/O design of new HP 9000 Models 705 and 710 entry-level workstations - Technical

Hewlett-Packard Journal, August, 1992 by Craig R. Frink, Robert J. Hammond, John A. Dykstal, Don C. Jr. Soltis

This paper presents the processor, memory, graphics, multimedia, and built-in core I/O design of the new HP 9000 Models 705 and 710 entry-level, scalable, PA-RISC workstations. The use of a buffered CPU/memory interconnect is important for scaling the high-frequency, high-performance processor design to the entry-level desktop.

The HP 9000 Models 705 and 710 (Fig. 1) are new, entry-level members of the Series 700 performance workstation family. They complement the higher-performance Models 720, 730, and 750 workstations (see article, page 6), offering lower cost and broad functionality. The Series 700 workstation products are based on Hewlett-Packard's PA-RISC architecture,(1) providing application-code compatibility across a broad range of applications. The systems address applications ranging from those characterized by cost sensitivity, diskless workstations, and grayscale graphics to those requiring higher-performance 3D color and maximum computational ability.

The 35-MHz Model 705 is designed for desktop applications that can benefit from 35-MIPS, 8.4-MFLOPS, and 34-SPEC-mark performance at the lowest cost.(*) The highly integrated graphics system design produces graphical user interface (GUI) performance exceeding 4800 (geometric mean) on the X11perf benchmark and 450,000 2D X11 vectors per second.

Cost-sensitive applications requiring even greater performance will benefit from the 50-MHz Model 710 color workstation. It produces 59-MIPS, 12-MFLOPS, 49-SPECmark performance. Its GUI performance exceeds 7290 (geometric mean) on the X11perf benchmark and 500,000 2D X11 vectors per second. This makes it an ideal platform for low-cost, 2D electrical and mechanical computer- aided design.

The Model 705/710 design produces an unparalleled level of desktop price, performance, and functionality in a quick-time-to-market design. Through the integration of system components and architecture and the leveraging of other Series 700 designs, the Model 710 was ready to ship in less than 12 months from the initial product concept. Both models support up to 64M bytes of memory, an 8-kHz-sample-rate voice-quality audio design, and built-in I/O interfaces including intelligent, 32-bit, DMA-capable SCSI II and IEEE 802.3 LAN. Both models also support both grayscale and color configurations.

This paper details aspects of the Model 705 and 710 design that were important in producing a single, reliable, low-cost, high-performance, grayscale and color desktop system design on an aggressive 12-month schedule. It also compares the processor and graphics performance of the Models 705 and 710 with respect to other desktop members of the Series 700 product family.

System Overview

The Models 705 and 710 are designed to meet the need for low-cost desktop systems while providing scalability to higher performance. A single system board design enables the Model 705 to offer a very low price, while frequency scalability enables the Model 710 to reach higher performance levels at approximately twice the price. The Model 705 is able to use lower-frequency components--PA-RISC CPU, floating-point coprocessor, and cache SRAMs--to meet lower-cost objectives. The Model 710 uses higher-frequency components to reach higher performance levels.

The single system board design for the Models 705 and 710 is shown in Fig. 2. It fits within a desktop package 14 inches deep by 16 inches wide by 3 inches high, with the system electronics integrated on a single printed circuit board. The package accommodates two 3.5-inch storage devices with fixed or removable media. To better accommodate multimedia applications, the package integrates a CD-ROM player with no increase in desktop area.

The Model 705 provides the following features:

* 35-MHz PA-RISC CPU

* 35-MHz PA-RISC 64-bit floating-point coprocessor (FPC)

* 32K-byte instruction cache

* 64K-byte copyback data cache, 64 bits wide

* 5-megabyte-per-second SCSI II interface (NCR53C700)

* 10-megabit-per-second IEEE 802.3 LAN interface (Intel 82596 with built-in ThinLan transceiver and AUI)

* 8M to 64M bytes of error correcting SIMM memory (8M bytes in diskless configuration only)

* Integrated 8-kHz, 8-bit, voice-quality audio

* 8-plane 1280-by-1024-pixel color, 8-plane 1024-by-768-pixel color, or 8- plane 1280-by-1024-pixel grayscale graphics

* Two integrated 3.5-inch 420- or 840-Mbyte fixed disk drives

* One of the following three removable media devices (uses a fixed drive position): CD-ROM, 3.5-inch PC-compatible flexible drive, or 3.5-inch 2.0- Gbyte DDS (digital data storage) tape drive.

* Two RS-232 modem-control serial ports

* 350-kbyte/s bidirectional Centronics port

* HP-HIL device interface for a keyboard and up to 6 other possible pointing or input devices.

The Model 710 enhances Model 705 performance and functionality with the following differences:

* 50-MHz PA-RISC CPU

* 50-MHz PA-RISC 64-bit floating-point coprocessor.

Processor Design

The processor consists of a PA-RISC CPU,(2) a PA-RISC floating-point coprocessor,(3) and separate instruction and data caches. It executes one instruction (integer or floating-point) on every clock cycle. The instruction cache and 64-bit data cache are accessed simultaneously, producing an execution rate exceeding 57 MIPS and 12 double-precision MFLOPS in the Model 710, and 35 MIPS and 8 double-precision MFLOPS in the Model 705.