PC

Olivetti Quaderno PT-XT-20 (1992) – part 2

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You might think that the machine is useless without a working HDD and no floppy drive, but that is not true. Quaderno has a small bootable “ROMDOS” drive with basic system files, COMMAND.COM, a RAMDISK driver (up to 320KB of EMS memory can be used and you still have full 640KB of conventional memory) and Interlink software. This drive is interesting, because it acts like a read-write one. You can edit config.sys and autoexec.bat (the changes are there even after shutdown, if the CMOS battery is ok or AC is connected). You can even copy files there, but if it’s more than a few KB, the system will crash hard (requiring you to
reinitialize the ROMDOS).

With Interlink, you can mount remote HDDs over a serial port. I used it to run VC (Volkov Commander) to edit the config.sys (no EDIT.COM in ROMDOS) and enable the RAMDISK driver. After this, I had my small but fast local storage (non-persistent) and everything bigger was started directly out of the remote HDD from another computer. This is a good way to test the computer before fixing the HDD or installing a flash/SRAM card in PCMCIA 1.0.

Olivetti Quaderno PT-XT-20 (1992) – part 1

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This little machine is an XT-class computer with 16MHz NEC V30HL, 1MB of RAM, double-CGA 640×400 graphics (AT&T6300/Toshiba compatible), MS-DOS in ROM and a 20MB Conner HDD (working in 8-bit mode). Its size and weight are halfway between regular laptops and handhelds (it is ultra-portable even by today’s standards). I got one three years ago and it was dead like almost all of them nowadays. The issue was “easily” fixable by replacing all the SMD capacitors. We replaced the ones on the logic board and the computer booted. However, the screen was not able to retain the contrast value, which made it hardly usable. Also the Conner drive had the head stuck (a common issue, that I want to fix later). We disassembled the lid and replaced a capacitor on the display board. Everything worked flawlessly when disassembled. As soon as we assembled the machine together, it stopped working. We were tired and put the whole thing into storage.

Recently, after three years, we gave the machine another chance. Disassembled it, booted and everything worked ok (except the HDD of course). After assembling it back? No sign of life… The issue was caused by too long legs on the new capacitor in the display board. The legs were sharp and went through the insulation layer on the (metalized) screen cover and shorted the capacitor (I know, shame on us…). Once we fixed this, we were able to put the machine back together and enjoy it. David also replaced cracked internal plastic parts using a 3D printer.

Now we have a trouble-free machine in a perfect shape with just one flaw – a faulty hard drive (and no floppy drive). However, that is not as big issue as one might think…

Early Apple Macintosh PowerBooks

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PowerBook 100 has a special place in my heart. I had one back in the 1990s and I loved its big trackball, comfortable keyboard and proper palmrest area – features that were not present in typical PC laptops. Other early PowerBooks were not as small and light as the PowerBook 100, but they shared many design decisions with it. I perfectly understand people who bought and used these computers when they were new. On the other side, I cannot agree with those who see early PowerBooks as universally superior machines to PC notebooks. That’s just not true.

From time to time, I see nonsense statements like that PowerBooks were the first laptops with stereo sound, optical drives, docking stations or other features. Not sure at the moment, but I think that you can find some of these statements even on Wikipedia. However, all of these features were previously available in PC laptops.

In fact, the generations of early PowerBooks that came after the first generation were not considered very innovative back then. Just a few examples:

  • Support for gray-scale video modes on internal screens was added at the end of 1992. Until that, it was possible to run only programs that were written to work with the black and white mode. All VGA-equipped PC laptops supported gray scale and could also translate colors into levels of grey in hardware (no OS or program support was required).
  • Unlike with PC laptops, there was no support for features like color LCD screens, PCMCIA expansion cards and microprocessors with built-in power management capabilities in 1992.
  • There was no graphics acceleration in Apple’s video circuits which resulted in significantly slower screen redraw. This started to be a problem when Apple offered PowerBooks with color screens where the graphics core had to process far more data. The first color PowerBooks with competitively fast graphics chips were available after Apple started to use generic PCI solutions from the PC world (mostly Chips & Technologies, later ATI).
  • Many of the PowerBook graphics chips didn’t support more than 256 colors on external screens even in 1994. Lower-end machines didn’t even have a video output for an external screen.

The first color TFT PowerBook – 180c – was released in August, 1993 – almost a year after major PC brands released their first TFT portables. The PowerBook 180c was equipped with a small 8.4-inch 640×480 screen when PC laptops often used 9.5-inch screens and there were some with even 10.5-inch screens (like the famous IBM ThinkPad 700C – December, 1992). That was not the only issue – it lasted only about an hour on one charge because (unlike PC laptops) it didn’t have a 3.3V CPU, advanced power management features and NiMH batteries.

Heat and power consumption was so big issue with Motorola 68040 that Apple had to release 040-based PowerBooks with a version of the CPU that didn’t have a math coprocessor. Thus, programs that used it heavily were twice as fast when running on the previous generation of high-end 030-based PowerBooks. 486DX-based PC laptops could run the same code four times as fast.

The machines on the photos:

(1) Apple PowerBook 100 (1991), 16-MHz 68000, 4MB RAM, 20MB HDD
(2) Toshiba T2200SX (1991), 20-MHz 386SX, 4MB RAM, 60MB HDD
(3) Apple PowerBook 145 (1993), 25-MHz 68030, 8MB RAM, 80MB HDD

ATI Graphics Solution rev 3 and monochrome ADI DM-14 (1985-6)

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My Vienna 286 (1987) has finally got a monochrome MDA monitor so I can put back the original graphics card (ATI Graphic Solution rev 3). This first ATI chip (CW16800-A) has functions necessary to drive CGA and MDA/Hercules modes, so you can connect both types of monitors although the card is very small. In fact, I was thinking that it was something much newer than the rest of the system but that was not true. ATI implemented most of the circuits in a big GAL (Gate Array Logic, maybe that’s why they were called Array Technologies, Inc.) which allowed them to make the card very compact.

I’ve started with MCGA graphics in 1989 and then with SVGA graphics in 1990. I had never had an opportunity to play with Hercules graphics modes, so I was extremely curious. Using high-resolution text-mode applications in an MDA mode (IBM Monochrome Display Adapter) is a pleasure on this long-persistence screen. Especially when you consider that the same experience was possible since day one with IBM 5150 PC in 1981.

Hercules Graphics Adapter (HGC) used almost the same signal timing as MDA and added a graphics mode where each pixel (720×348) could be changed independently. This allowed business applications to use high-resolution monochrome graphics (black/white) and the card became quite popular (ATI was not the only company making HGC clones).

HGC mode is not the best choice for gaming. Although a lot of games supported the HGC mode, they usually used a simple hack with CGA data. These were the typical approaches:

  • Prince of Persia: 320×200 CGA graphics is horizontally stretched to 640 pixels where each two adjacent pixels are used for dithering (4 shades -> 2 shades). There is no vertical expansion used in the game. The developers just put the 200-row graphics in the center of the 348-row screen.
  • Stunts improved the approach used in Prince of Persia. There is always a black row after two standard rows, so the screen is expanded to 300 rows. I’m surprised that it doesn’t look bad at all on the real CRT.
  • F-15 Strike Eagle tries to expand the graphics to the whole screen area. The vertical expansion is done by doubling every second row.
  • Microsoft Flight Simulator 3.0 looks great because it works with vector graphics. Thus, it can use the full HGC resolution. The result is better than with CGA with exception of the 16-color composite CGA output.

Beware of Dead RTC/Backup Batteries (Again)

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It took me half a day to get mostly dead RTC and RAM backup batteries from two desktop and six notebook computers. In 50% of cases the batteries already started leaking so they would soon kill the computer.

I didn’t replace the batteries with new ones as I don’t need another ticking bomb in my old machines. Now I have to access BIOS setup every time I want to use the computer. That’s the only drawback but I can live with it.

MS Flight Simulator 3.0 on Quaderno

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MS Flight Simulator 3.0 running on Olivetti Quaderno PT-XT-20. Although only XT-compatible, 16-MHz NEC V30 is five times faster than original PC with 4.7-MHz Intel 8088. This means that the game is perfectly playable on this machine.

The internal 20MB Conner hard-drive is defective and needs to be repaired. However I am able to share a hard drive from another computer over a provided null-modem serial cable thanks to somebody in Olivetti who decided to add interlnk.exe and intersvr.exe to the C: ROM drive.

Quaderno Resurrection

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After several hours and twenty replaced capacitors this Olivetti XT-compatible sub-notebook is finally alive. Yay!