**** Cassettepunk ****

Technological Surrealism / Alec Nerds Out

“PCsr” Home Computer Chimera

The PCsr is presented here as a rare specimen of a 1980s-era home computer. Yeah, yeah, so it never existed until now.

This one started as an 8mm film editor spotted in a junk shop. It cried out for a screen replacement and computer installation. The fiddliest part of the whole thing was clearly going to be finding a screen that fit, so I started there and everything else followed.

The stock Goku editor was basically a lamp, a couple of mirrors, and a Fresnel lens. It was a triumph of optimized 1970s-era Japanese manufacturing; all the materials are the cheapest possible to obtain a fully satisfactory result. Several apparently metal parts where chromed plastic, and the metals themselves are hilariously brittle, but nothing felt like it threatened the utility of the product and nothing stood out as incongruously cheap.

As recently pointed out by Quinn Dunki over at Blondihacks (whose homemade 8-bit Veronica is everything this project is not), it’s getting hard to find much selection in 4:3 aspect ratio LCDs. She ended up going with a security display; I lucked out and found a perfect size match on Alibaba courtesy of Dalian Good Display. This was my first experience using Alibaba and I was mentally prepared for a scam, so when my order expired and Lisa over at Dalian wrote a message apologizing and inviting me to pay directly, I thought I was being had. I re-placed the order through the broker and it came promptly and exactly as promised — clean and working. My only complaint is that they used a through-hole VGA connector at the end of the cable and secured it with a mess of hot glue.

Lesson learned: Alibaba works, and I was way too suspicious about it.

Speaking of VGA: This requirement was the price I had to pay for a perfectly-sized display. Now I had to find a small single-board computer to drive it. I ran through Wikipedia’s list to find something suitable that supported VGA, and settled on an OLinuXino A13 (made by Olimex). This is built around a 1GHz Allwinner A13 ARM chip, which has been pretty popular for Android tablets but also runs Linux half-decently. (More in a sec on what “half” means.)

This turned out to be the perfect form factor and sufficient power to generally do whatever I needed. But a few words on the A13, as there were some annoyances:

Allwinner, who makes the chip the A13 uses, is not known to play by the Open Source rulebook as I know it. Reading about this led me to the term “gongkai”, which was coined over at bunnie’s blog to refer to the practice of operating in an open source/intellectual property gray area. (It’s a good read.) In any case, there are some pretty angry interactions between Allwinner and the FOSS community, and it seems that the end result is that support (e.g. for multimedia) on Linux is not as good as it could/should be on these boards.

There are a couple of nuisances specific to the Olimex board. I purchased the wi-fi version of the A13, which includes a small soldered-on daughter board with a Realtek wi-fi chip on it. I didn’t test this with the built-in Android distribution but started working with the Olimex Debian image, and immediately found that the wifi chip was functioning very intermittently. This seemed to be caused by the Realtek chip overheating. Others encountered similar problems but there doesn’t appear to be a solution. I ended up unsoldering the daughter board and using a USB wifi adapter — ironically, with the identical chipset — but this is hardly what I wanted from a 10€ upgrade. I’ve also found the board to be not perfectly stable under certain conditions though I suspect the chip is likelier to be the problem than the board.

Overall, the lesson here is that a gold Open Source star is clearly more than an ideological concern; its absence here definitely affected my experience using the board.

The basic configuration of the A13 board is done using a FEX file on the boot filesystem. To get it working at the VGA display’s 640×480 resolution, I had to tweak a few parameters:

--- script.fex 2014-12-22 16:12:23.624030186 -0800
+++ script.fex 2014-12-26 21:02:50.000000000 -0800
@@ -175,7 +175,7 @@
ctp_name = "ft5x_ts"
ctp_twi_id = 2
ctp_twi_addr = 0x70
-ctp_screen_max_x = 800
+ctp_screen_max_x = 640
ctp_screen_max_y = 480
ctp_revert_x_flag = 0
ctp_revert_y_flag = 0
@@ -219,16 +219,16 @@
lcd_used = 1
lcd_x = 640
lcd_y = 480
-lcd_dclk_freq = 33
+lcd_dclk_freq = 25
lcd_pwm_not_used = 0
lcd_pwm_ch = 0
lcd_pwm_freq = 10000
lcd_pwm_pol = 0
lcd_if = 0
-lcd_hbp = 46
-lcd_ht = 1055
-lcd_vbp = 23
-lcd_vt = 1050
+lcd_hbp = 100
+lcd_ht = 845
+lcd_vbp = 34
+lcd_vt = 1060
lcd_hv_if = 0
lcd_hv_smode = 0
lcd_hv_s888_if = 0

I also had to recompile the kernel to get Logitech Unifying Receiver support included for the sake of the keyboard/trackpad.

With the screen and Olimex board mounted (a couple of improvised brackets and some paperclips did the trick) I had to decide what to do with it. I had a few ideas…

  • Make a media player/video editor. This most closely preserved the original function of the device, but with new technology.
  • Make a retro-looking computer. I had a couple of ideas here…
    • Make the spools into a reel-to-reel tape drive. Conceptually this would’ve been beautiful but after battling with 8-track fidelity that would’ve been a lot of work to cover familiar territory.
    • Make a Frankenstein multimedia home computer, using the spool arms as stereo speaker mounts. This is what I ended up doing.

Let me explain the concept a little more. I got into computers in the late ’80s as a pre-teen, often by scrounging obsolete machine at garage sales or even school dumpsters. I had a CoCo, Osborne 1, Compaq Portable, Timex Sinclair, a Wang of some sort (not this one exactly), numerous C64s, a 386 PC, and much more. Pretty much anything that didn’t have an apple on it. The diversity of machines was spectacular and each had its own loyal following.

Standardization gradually entered in various ways: pointing went from light pen or joystick or arrow keys to the mouse we all know. Luggables evolved into conventional laptops. And so on, but with lots of failed experimentation along the way.

I decided to make this project into a weird and somewhat wrong could-have-been. It looks a bit like a “shrivelled Macintosh” (thanks, Ingo), has a wireless Chiclet keyboard like the much-hated PCjr did, and had built-in stereo speakers like a ’90s-era Compaq Presario. (I really hated working on Presarios.)

It’s not apparently expandable, though there are a couple of hidden USB ports and an SD card slot.

On the front, there’s a power switch, 1/4″ headphone jack, and volume control thumbwheel (where the focus knob used to be).

Software-wise, it runs Debian, but configured to boot into a very plain desktop that offers a few of the typical things that would’ve come with an ’80s-’90s-era desktop: Solitaire, Minesweeper, Calculator, Notepad, Doom, King’s Quest IV, Alley Cat, etc.:

A full Linux desktop including a web browser is available, but hidden. (You need to hit the bottom of the screen with the mouse to bring up the toolbar.)

Both hardware and software aspects are intended to be Frankensteined together without reference to historical accuracy — this is my childhood we’re talking about, not a museum.

(p.s.: I’m pleased to have had a chance to sneak my Yamaha SY-1 in for the soundtrack.)
(p.p.s.: For the first special snowflake to complain about me destroying antiques, this is for you: Spend $20 and go get your own.)
(p.p.p.s.: I’ll be exhibiting again at the Culture Crawl in Vancouver in November. Come see me.)
(p.p.p.p.s.: Thanks, Gnome desktop applications, for sometimes looking a lot like 1992. I was able to use you without adaptation. Much love. No, really.)

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  1. […] tape) back together. It’s sad to see these in junk stores, but great for [Alec] who thought it begged to have an LCD and a single board computer implanted in it.  Once the editor was in hand, the machine was gutted of its very simple parts: a lamp, some […]

  2. aldolinux80 says:

    J’adore !

    Quite impressive!!!
    Thank you for sharing this experience, it makes you want to go for old objects to recycle into a PC!
    I think I’ll try.

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