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Quorten Blog 1

First blog for all Quorten's blog-like writings

Great website info on a historic Macintosh hardware engineer

quorten

2020-08-12

Categories: mac-classic  
Tags: mac-classic  

The Bob Bailey Unit, or BBU for short, an important address and I/O signals logic chip for the Macintosh SE. Really, what more information is there behind the namesake of Bob Bailey? Here is a great site for such information, from one of the very folks who worked closely with Bob Bailey in the Apple Integrated Circuits group. Very interesting, how Apple developed their whole integrated circuits design group in the Macintosh department.

Yep, the RTC chip was wholly engineered inside of Apple, and a considerable challenge at that. Actually, come to think of it, in many ways it was one of the first of its kind to bring a battery-backed RTC to the PC market.

20200812/DuckDuckGo macintosh bob bailey unit
20200812/http://www.byrdsight.com/apple-macintosh/

My definition of fair market rates in software, a summary of important sectors of the general business world, and constraints to software employment by a big business

quorten

2020-08-10

Categories: personal-finance  
Tags: personal-finance  

So, I’m getting more into games of modeling the financials of various different companies, and one thing that has occurred to me was that I haven’t ever really thought very much about the financials of running a software company. I’ve thought far more about the financials of a back-end customer buying software or software services from a company. And, here’s the point. Both sides are valid and important to consider.

The primary reason why it’s so easy to understand and model the financials of non-tech companies is because, well, they are, by definition, much slower moving disciplines than the tech profession. The rules of those games don’t change very quickly, so it is very easy for a hobbyist (more specifically, someone who only has third hand experience of those industries but a lot of it from their past life experience) to be able to model the financials of these companies with a lot of accuracy. But the tech sector? That’s a moving target.

One of the big things to realize, and that we all agree on, in the tech sector is that prices are constantly going down. This provides an obvious benefit for the customer: in the future, the customer will be able to buy more technology capability for less money. And by being able to do so, a greater number of people in the world will be better empowered by advanced technologies as time goes on.

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BJT transistor emitter-collector understood

quorten

2020-08-09

Categories: raspberry-pi  
Tags: raspberry-pi  

Almost every BJT transistor architecture construction diagrams shows a symmetric device. So, is there really any difference in operating a BJT transistor if you swap around emitter and collector? Indeed, there is, and it is due to the fact that these are always simplified diagrams. Generally, one of the two sides is more heavily doped and/or larger than the other. So this is what makes the transistor perform much better when operated one way than the other. However, it is still possible to operate the transistor with emitter and collector reversed, it’s just that you can only do so with a much smaller current. The particular niche application where you got better specifications on one parameter was all but replaced by modern MOSFETs instead.

20200809/https://en.wikipedia.org/wiki/Bipolar_transistor_biasing
20200809/DuckDuckGo what is the difference between emitter and collector
20200809/https://www.physicsforums.com/threads/difference-between-emitter-and-collector.800420/

IWM, SWIM, and Apple schematic design templates

quorten

2020-08-08

Categories: mac-classic   important  
Tags: mac-classic   important  

Important! Looking for information on how the IWM/SWIM works? Looking for some legible scans of Apple-style schematics so that you can copy stationary template patterns to an illegible scan that you are reconstructing? Look here, there’s lots of great information at this area on the Internet Archive, looks like it was submitted directly by Apple themselves.

20200807/https://archive.org/details/SWIMDesignDocs

NinjaTek, 3D printable synthetic rubber

quorten

2020-08-07

Categories: 3d-printing   mat-sci  
Tags: 3d-printing   mat-sci  

It’s here! NinjaTek, 3D printable synthetic rubber. But… when? Okay, this is actually quite old, it’s been around for like 5 years? So, really, it’s not like this is recent innovation to be able to 3D print rubber on FDM (Fused Deposition Modeling) printers.

20200805/DuckDuckGo ninjaflex
20200805/https://www.bhphotovideo.com/c/product/1407488-REG/ninjatek_3dnf1417505_ninjaflex_tpu_flexible_filament.html/?ap=y&smp=y&msclkid=9093c8df674510961bce97f4e5329d82
20200805/https://www.amazon.com/NinjaFlex-TPU-3D-Printing-Filament/dp/B00WFD94E8?th=1

Lots of great tech: RaSCSI, Scuznet, MacOS cross compile, and more

quorten

2020-08-07

Categories: vintage-computing   mac-classic  
Tags: vintage-computing   mac-classic  

The user Uniserver on 68kMLA? Here is his website. Apparently he has made a number of his own schematics, but he requires payment before you can download it.

20200805/http://www.maccaps.com/MacCaps/Schematics.html

The available schematics mostly focus on newer classic Macintosh models, pretty much the oldest one on the list is the Macintosh SE/30. And that one, well nowadays that has a more openly available schematic.

Good news, RaSCSI has plans of adding support for SCSI network adapters! In the meantime, there is Scuznet, available as a standalone board project.

https://68kmla.org/forums/index.php?app=forums&module=forums&controller=topic&id=30399&page=6&app=forums&module=forums&id=30399
https://68kmla.org/forums/index.php?app=forums&module=forums&controller=topic&id=59044&page=2&app=forums&module=forums&id=59044

Here is the GitHub for the 68kMLA version of RaSCSI.

20200805/https://github.com/akuker/RASCSI/wiki/OLED-Status-Display-(Optional)
20200805/https://github.com/akuker/RASCSI/wiki/Setup-Web-Control
20200805/https://github.com/akuker/RASCSI

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Reverse engineering the Macintosh SE main logic board project, how to digitize a multilayer PCB

quorten

2020-08-02

Categories: vintage-computing   mac-classic   raspberry-pi  
Tags: vintage-computing   mac-classic   raspberry-pi  

This is a very interesting 68kMLA thread on reverse engineering the Macintosh SE main logic board and custom chips. And… now I’ve made myself also become a key contributor!

20200802/https://68kmla.org/forums/index.php?app=forums&module=forums&controller=topic&id=60059&page=5&app=forums&module=forums&id=60059

So, how do we start out? We need to obtain scans of the main logic board, depopulated of all discrete components. Indeed, this is bringing to full fruition an idea I had before about reverse engineering existing electronics. But, the means and methods go even further than that. How do you do this with internal layer printed circuit boards? The approach is, well, quite clever, though it involves brute force. In general, you actually can’t shine bright light at a PCB and hope to see shadows of the internal layers. However, you can take a grinder to the surface to grind away the top layers. The internal layers will then be visible and you can scan them accordingly. Yes, unfortunately, it is a destructive process, so you really do need spare copies on hand unless you think you can get it right the first time!

Commodore 64 on an FPGA? Yes, it’s happened. Ultimate 64 Elite is the name of the game. Look here.

20200802/https://ultimate64.com/Ultimate-64-Elite

Searching for Open Hardware designs in vintage computing, history of Floppy Emu, and the crux of mass production and Open Hardware

quorten

2020-08-02

Categories: vintage-computing   apple-ii   mac-classic  
Tags: vintage-computing   apple-ii   mac-classic  

It’s coming! I’m going to have clean, clear, and precise models of my vintage Macintosh hardware that I own, maybe even sharp enough to manufacture a replica of the hardware. Now, wouldn’t that be swell?

More importantly, for my own personal interest, wouldn’t it be swell if I could have a full physical model of my original hardware in virtual space, and only ever need to interact with the virtual model forever more? It would provide everything that the physical model would, without any shortages due to computation speed limits on computers or limits on the features implemented by the emulator that strives for speed by sacrificing accuracy.

So, here we go. For classic Macintoshes. First stop, ROM replacements.

Macintosh 128K, 512K, 512Ke: ROM-inator, Open Hardware, design files available. Check it out. Designed in Eagle because it’s rather old. But, wait… where’s the source? Okay, maybe not totally Open Hardware, but at least there is a refrence design available for you to look at.

20200801/https://www.bigmessowires.com/mac-rom-inator/

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QEMU now supports PPC Mac emulation!

quorten

2020-08-01

Categories: mac-classic  
Tags: mac-classic  

Wow, this is great. After visiting this site, I saw that QEMU now supports Mac OS 9 PPC system emulation! That means I don’t have to juggle around another bespoke emulator system when emulating Mac OS 9. Old PCs and old Macs, they can both come from QEMU, along with modern virtualization from KVM. Super-slick.

20200801/https://www.macintoshrepository.org/
20200801/https://www.emaculation.com/forum/viewtopic.php?f=34&t=9028&p=53807#p53788
20200801/https://www.emaculation.com/doku.php/ppc-osx-on-qemu-for-windows

Recycling solder waste revisited

quorten

2020-07-30

Categories: raspberry-pi   mat-sci  
Tags: raspberry-pi   mat-sci  

After you’re done with soldering, you’re left with a solder sponge with minute amounts of solder in it. If you are using leaded solder, that contains minute amounts of lead. So, you shouldn’t just throw that in the trash, now should you? Previously, I’ve searched for info on this subject, and the consensus was this. If you’re just doing it personally for hobby electronics, it’s perfectly fine to throw it in the trash, that’s what your garbage and recycling companies will typically instruct you on. Because you’re not a business, the quantity isn’t big enough to be a concern. But, if you search for “recycle solder waste,” you will get a few options brought up.

So, the key to revisiting this subject. Some recycling companies are less generous than others in what they are willing to recycle. Indium Recycling does not recycle solder wipes, these have to be sent to a different recycler.

On the other hand, Alpha Recycling Services does recycle solder wipes. They will also recycle solder paste, so long as there is metal content within it, so that’s your go-to for recycling solder paste. And, by extension, you can ask them about recycling. Brass solder scour pads are also, in effect, copper with solder in it.

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