Commodore's Amiga line of computers has carved an interesting niche for itself in the video industry. Despite it's great strengths in this realm, primarily through third party products like the Video Toaster, the Amiga has suffered from relatively out of date native video displays. While Macintosh and PC computers have enjoyed robust support for 8 and 24 bit graphics for many years now, the Amiga has only recently been upgraded to 8 bit native graphics with an odd hodgepodge of solutions for "true color" display capability.
With the proliferation of low-cost, high performance graphics chip sets for the Mac and PC, third parties have begun to incorporate them in expansion cards for the Amiga. The EGS Spectrum 28 card from Great Valley Products, a long-time Amiga peripheral manufacturer, represents one of the more impressive efforts.
The Spectrum 28 is a smallish card that easily plugs into any Amiga equipped with a Zorro II (16 bit) or Zorro III (32 bit) expansion slot. The card automatically detects which type of slot it occupies, which dramatically effects it's performance. In either slot, the card is capable of displaying an impressive array of resolutions, depending upon on-board Static DRAM:
In deference to it's Amiga host, the card also supports "video" resolution modes with interlace and extreme overscan. The Spectrum's chip set is highly programmable and, through a provided utility, allows you to tailor new display modes to specific monitors or applications. However, the output of the Spectrum is not inherently video compatible -- it cannot accept external sync -- requiring solutions similar to those available to the PC and Mac. Due to the variety of resolutions available, a multisync monitor is highly recommended.
As the card resides on the Amiga's expansion bus, it has direct access to the processor and main system memory, unlike the Amiga's native graphics chips that must share it's dedicated memory with the processor. This allows for excellent performance, despite the Spectrum's lack of fast hardware for fills and zooms, especially on systems with hi-speed processors. Even a 68030 based Amiga 3000, equipped with a Spectrum 28 can handsomely outperform a standard 68040 based Amiga 4000 in equivalent native display modes, with the option to far exceed it's display resolution and depth.
The Spectrum 28 provides two connectors, a DB-15 RGB out for it's own display, and a pass-through connector. The pass-through allows the user to toggle between native Amiga generated screens and Spectrum generated ones when using a single monitor. This creates a greater level of software compatibility, letting programs that are unable to address the Spectrum hardware to run unimpeded. This is of particular significance to Video Toaster and OpalVision users, which use non-standard displays. The board will effortlessly pass-through RGB sources that have been genlocked, such as the native Amiga or IV-24 displays, if desired.
The Spectrum also facilitates multiple monitor configurations with the use of it's "MultiGFX" technology. Similar to Macintosh virtual monitor displays, an Amiga can be equipped with multiple Spectrum cards, allowing the cursor to pass effortlessly from monitor to monitor, regardless of resolution.
While the hardware is quite frankly superb, the chief concern and major issue is software performance and compatibility. In this area, GVP has adopted two solutions: a special driver that hooks into the Amiga's Display Database and a separate, completely new graphical user-interface. Each achieves varying degrees of success.
Most current Amiga applications can be directed to any of the Amiga's display modes through the Display Database requester. Since the Spectrum 28 software hooks into this feature, any application that complies with Commodore's programming guidelines can tap into the Spectrum 28's display, in theory. In practice, however, many applications do not like this. GVP affirms that they address the machine in a compatible way, leaving the onus on applications developers to check their interface guidelines. As the Workbench can be retargeted to the Spectrum display, well-behaved Workbench residing applications can almost certainly benefit from the increased resolution and speed.
Besides the incompatibility problems with the above method, which presumably can be fixed by minor software updates, there are other problems as well. The Spectrum does not emulate certain Amiga interface niceties such as pull down screens. Also, the Amiga operating system imposes a limit of 256 colors for native applications, negating the Spectrum's full color capabilities. Until Commodore implements an upgrade to their system software, there is no direct support for 24 bit displays under this scheme.
The Enhanced Graphics System, or EGS, was developed by Viona Development to serve as a high end graphics standard for the Amiga and is supported by the Spectrum 28 hardware. Similar in appearance to Motif or Open Look on Unix-based platforms, it has all of the windowing, cursor, and menu driven functions we've all become accustomed to. EGS, however, has the added benefit of supporting extremely high resolution displays, 24 bit color, and an emerging crop of Amiga-based display cards.
GVP includes the EGS system software with the Spectrum card, bundled with various utilities, test programs, trifling games, and a serious application, Spectrum Paint. In it's 1.2 incarnation, Spectrum Paint proves to be a moderately useful paint package, with effective tools for stenciling and a well-implemented pantogragh feature. It does lack many features we become accustomed to in more mature packages, such as custom brushes, multiple file format support, animation, and -- a particular bugaboo of mine -- no viewable 24 bit brushes, only a 2 color representation. The 2.0 software will address many of these limitations.
The success of the EGS strategy lies in the level of support it receives from third party developers. EGS applications have been slow in coming and literally number only a handful, but releases or forthcoming including a version of PageStream, the premier Amiga desktop package, which will run on EGS. GVP also promises, along with the major upgrade to Spectrum Paint, an EGS version of Image FX, GVP's own image processing software. But the specter of Commodore's long-promised RTG standard might continue to put a damper on EGS in regards to third parties.
GVP must also overcome another significant difficulty: making the software robust enough to withstand the odd combinations of peripherals that are now possible within a single machine. Of the three systems tested -- an accelerated A2000 equipped with a Video Toaster, a plain vanilla A4000, and an IV24 equipped A3000 -- only the A3000 proved to be an unqualified success. The other systems showed various levels of software idiosyncrasies and failure.
My A4000 never effectively retargeted the Workbench or other Amiga applications, even though EGS applications worked as expected. Such problems are supposedly rare, with prospective A4000/Spectrum 28 owners needing to check on the revisions of the "Buster" DMA controller chip and the CPU daughter board for compatibility. Otherwise, the Spectrum 28 promises the best performance in an A4000 than any other standard Amiga model.
The A2000 Toaster system was able to run the Toaster applications, along with a fully functioning EGS Spectrum Paint just a mouse move away on a separate display, making Toaster Paint an irksome memory. My particular system configuration, with limited 32 bit memory and a small mix of 16 bit memory, had problems with multitasking and application conflicts. As with any system, the more memory the better, and the Spectrum software is no exception needing at least 512K of free RAM to function. Die-hard Amiga 2000 Video Toaster users can find the Spectrum 28 as a way of breathing new life into their systems.
The A3000 on the other hand, acted in a way that GVP must consider to be the model of performance. Coupled with GVP's own IV-24, the combination created an excellent RGB image capture and processing system.
The Spectrum 28 is a classy addition to an Amiga system, if a bit pricey ($499 for the 1MB, $599 for the 2MB) the same type of graphics chip set being available on PC video cards for only half the price. But then that card would be in a PC, not in an Amiga. Also, while videophiles may lament the lack of true video compatibility, the Spectrum was designed to provide high resolution, true color displays, which it performs admirably. Considering the excellent inter-process communication and multi-tasking facilities of Amiga computers, the Spectrum 28 and EGS open the way for inventive multimedia system developers to create very powerful turnkey stations. With control and application screens residing on the Spectrum card, the Amiga chip set bus would be free to concentrate on NTSC compatible video instead of CPU contention.
Between enhanced or stringent Display Database support and the EGS, developers have good options in making the Spectrum 28 a great Amiga peripheral.