dtj v03-04 1991

This issue of the Digital Technical Journal, Volume 3, Number 4 (Fall 1991), focuses on Digital Equipment Corporation's advancements in Image Processing, Video Terminals, and Printer Technologies. The overarching themes are delivering high-performance, user-friendly solutions in multi-vendor, networked environments while adhering to open standards.

The journal presents several technical papers addressing key challenges in these areas:

1. Hardware Accelerators for Bitonal Image Processing: This paper details the design of DECimage hardware accelerators (DECimage 1200) to manage the large data size of bitonal images. These accelerators improve display performance (decompression, scaling, clipping, rotation) and enhance image legibility, offering an interactive viewing experience for document management applications on X terminals.
2. X Window Terminals: This article traces the evolution and design of Digital's X window terminals (VT1000, VT1200, VT1300, VXT2000). It highlights their role as cost-effective alternatives to workstations, discussing design choices related to hardware platforms, window management, X server implementation, and support for various network protocols (LAT, TCP/IP) and font file systems, all within the client-server model.
3. ACCESS.bus, an Open Desktop Bus: This paper introduces a new open desktop bus standard based on I²C technology. Designed to simplify the connection of low-speed I/O devices (like keyboards, mice, and tablets) to desktop systems, ACCESS.bus features dynamic reconfiguration, hardware arbitration, and a generic device grammar for plug-and-play interoperability across different vendors.
4. Design of the DECprint Common Printer Supervisor for VMS Systems: This article describes the DECprint Common Printer Supervisor (CPS), a software component for VMS printing systems. CPS controls a wide range of PostScript printers, manages multiple media types, handles various I/O connections and communication protocols, and performs data syntax transformations to insulate applications from specific printer details.
5. The Common Printer Access Protocol (CPAP): This paper explains the Common Printer Access Protocol (CPAP), which provides fundamental services for data presentation and accounting in heterogeneous, internetworking environments. It emphasizes its compatibility with older protocols and its acceptance by the Open Software Foundation (OSF), demonstrating Digital's commitment to industry standards.
6. Design of the Turbo PrintServer 20 Controller: This article details the design of a performance-enhanced PrintServer 20 controller. It focuses on achieving five to eight times the throughput for complex PostScript documents compared to its predecessor, discussing the use of existing chips for cost efficiency and the application of a performance analysis tool (RETrACE) in its development.

Collectively, the papers underscore Digital's strategic focus on creating robust, high-performance, and standardized computing solutions for visual and hard-copy data in distributed network environments.