A periodic fascination on this blog is figuring out better ways to get better screenshots of our classic systems, which often hail from the Wild Wild West/East in terms of video standards (
read all entries in this series). Naturally the best way is a bitwise direct grab of the framebuffer, but that's only possible if there's sufficient operating system support. This support is obviously absent for things like boot messages (especially important when investigating
NetWare on the Power Mac 6100), so we need to figure out a way to capture that information. My capture box of choice is currently an Inogeni VGA2USB3, which is small, self-contained, USB-powered, highly compatible and makes high quality grabs of anything you can wire into composite or a VGA HD-15 connector up to 1080p, but is limited to 60Hz refresh rates. Various solutions like the OSSC exist, but these are more oriented to arcades and consoles rather than (our primary interest) workstations, and the Pro in particular isn't cheap.
While you might be able to trick the hardware into emitting a compatible signal, that's not good enough or even possible with several of my machines. Previously my problem child was astro, my SAIC Galaxy 1100, a modified PA-RISC HP 9000/712 crammed into a MIL-SPEC portable case with a fabulous built-in flat panel. These machines ran HP-UX 10.10 in their original heyday, but this particular system runs NeXTSTEP 3.3 for PA-RISC during the brief period of time NeXT supported the architecture and was a big hit at the Vintage Computer Festival West a few years ago. Its flat panel runs at an odd 62Hz and the external VGA port only generates a 60Hz signal for 640x480 (all other resolutions use different refresh rates), which is hopeless for running NeXTSTEP. However, now I have a new candidate I'd like to get some grabs off: a particularly problematic member of the Atari ST family which has been the subject of a long-running and highly frustrating extended Refurb Weekend. You'll get to meet this bad girl soon enough. The standard ST high resolution mode is 640x400 — at 71.2Hz. I can get a picture from it with my trusty NEC flat panel, but not with the Inogeni.
The usual solution to this is a scan converter, but those can be expensive and inconvenient. Here's one I picked up used on eBay for $2. Yes, really. It cost more to ship it.
This is the Hall Research Technologies SC-VGA-2, sold as a "VGA/HDTV Video Processor." In addition to slicing, dicing and pureeing, apparently, it will take any of a bundle of input formats and both rescale and resample them on the fly into the VGA or HDTV signal you desire, including 60Hz rates. This came from a seller specializing in teleprompter equipment and Hall still sells
an HDMI version with additional resolutions ... for around US$500. However, this or the slightly newer
SC-VGA-2A and
SC-VGA-2B are all relatively common devices and found substantially cheaper used. Let's try it out and show some sample output, including those delicious NeXTSTEP system messages and some ST grabs.
