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Marek Karcz
computer programmer, electronics hobbyist/tinkerer, retro computing/8-bit enthusiast, commodore 64 user/programmer, arduino, raspberry pi
computer programmer, electronics hobbyist/tinkerer, retro computing/8-bit enthusiast, commodore 64 user/programmer, arduino, raspberry pi

Marek's posts

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Dueling Banjos : retro-computers edition.

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Restored few old laptops. They were in very good shape in the first place, so not a lot of work went to them.
1) Acer 950X, manufactured in 1996, running Windows 95. CMOS battery integrated with motherboard dead - replaced with CR2032 (slightly modded to achieve this). Pentium 120 MHz, 40 MB RAM, 800 MB HDD, 3.5" floppy, all in working order.
2) Dell Latitude Cpt C-Series (C400GT) model PPX, Graphics Controller - NeoMagic 2360, CPU - Celeron 400 MHz, 256 MB RAM, 10 GB HDD, CD-ROM running Windows 2000 Pro. Manufactured in year 2001. Replaced the battery (old one was dead, cost $16), missing key (used keyboard off eBay for $6) and equipped with PCMCIA WiFi (Linksys WPC64G, purchased as new-old stock for $10). System is still usable today (with some software updates, but barely). Computer has no Ethernet adapter and only one USB port.
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Got a new Hohner Blue Harp from my son under Christmas tree. This is the result of 30 minutes practice. Apparently I have a lot of room for improvement, but the harmonica sure sounds great - much better then cheap plastic one from known biggest retailer.

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Video, keyboard, sound for MKHBC-8-Rx.
Update on MKHBC-8-Rx project. While I still need to put RTC + Banked RAM circuit to the more permanent prototyping board (currently on a breadboard), I am already thinking about next step - a user I/O for my system, so it becomes a fully self contained syst...

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Sometimes, all you need is a different way of looking at a problem...

Found at: (

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Parallax Propeller 1 is already 10 years old, but it has pretty cool unusual (or perhaps should I say - 'niche') architecture for a micro-controller. It is an 8-core (cores are called cogs on propeller) parallel computer on a chip with each core running at 20 MIPS and having video generating capability built in (each core!). Each core has its own private memory and registers but there is also shared memory and round-robin style multiplexer that provides access to shared resources for each cog in equal slices of time. There are no interrupts in this chip because you don't need them. You just run the process in a separate cog if you need to have a dedicated service for any event. I purchased the P8X32A Quickstart 40000 Rev. A board 2 years ago and just found it in my drawer :-). So I purchased also C3 board and human interface shield for Quickstart and I am ready for some serious experimenting and learning to program in SPIN and prop assembly. Fun!
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CP/M : Tetris Clone in Turbo Pascal 3.0.
being an 8-bit era MS-DOS equivalent, a platform for
professional/business software had the advantage over most home
computer platforms of that time, which were usually equipped and
stuck with BASIC as their main programming language and operating
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