A Secret Apple Silicon Extension to Accommodate an Intel 8080 Artifact

Posted on November 16, 2022 by Blake Patterson

Lately I’ve been spending time on Mastodon for … reasons. Here’s my link: https://oldbytes.space/@blakespot. In my recently active time on the platform, I have found quite a few excellent retrocomputing-related posts by creative members of the community. One such post, by Dougall, links to his blog post entitled “Why is Rosetta 2 fast?“.

Rosetta 2 is the ahead-of-time compile translator that’s part of macOS Big Sur (and later) that, upon launch of an x64 Intel binary, translates it to 64-bit ARM code for execution on ARM-based Apple Silicon processors before execution. It is not a real-time emulator. It translates the entire binary — once — at launch time, making best-guess choices along the way. Dougall delves into various aspects of Rosetta 2 in an effort to explain why it is so performant; in many instances the translated binary runs faster on Apple Silicon than on the fastest Intel machines that Apple has ever released. It’s impressive.

It’s a fascinating read for a tech nerd like me that has a particular interest in OS technology. But one detail of the post really grabbed my attention.

Apple’s secret extension

There are only a handful of different instructions that account for 90% of all operations executed, and, near the top of that list are addition and subtraction. On ARM these can optionally set the four-bit NZVC register, whereas on x86 these always set six flag bits: CF, ZF, SF and OF (which correspond well-enough to NZVC), as well as PF (the parity flag) and AF (the adjust flag).

Emulating the last two in software is possible (and seems to be supported by Rosetta 2 for Linux), but can be rather expensive. Most software won’t notice if you get these wrong, but some software will. The Apple M1 has an undocumented extension that, when enabled, ensures instructions like ADDS, SUBS and CMP compute PF and AF and store them as bits 26 and 27 of NZCV respectively, providing accurate emulation with no performance penalty.

Intrigued by mention of this “secret extension,” I reached out to the author and asked if he could expand on what Apple has done here. And, he obliged. As he explained in his multi-part Mastodon response:

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Posted in Macintosh, OS | Tagged , , , , | 13 Comments

“4K Scaling” Is Not a Problem on Modern Macs

Posted on November 8, 2022 by Blake Patterson

I found myself posting this information so frequently on forum threads and in video comments that I wanted to put it all together in one place so that I can share my experience and what I’ve learned with a single link. And, while this is primarily a vintage computing blog, not every post is of that nature. Apologies to my retro-only readers. (Well, there is an Amiga and a Lisa in that second photo down the page, there, so…)

I recently replaced my aging 2017 5K Retina iMac with a Mac Studio, powered by an M1 Max processor and 32GB of RAM. Some months earlier I upgraded my aging laptop to a 2022 M2 MacBook Air. That iMac’s beautiful 27-inch, 5K retina display was hard to part with, and so I wanted to give the new desktop system a very nice screen. And I have, in the form of an LG DualUp 28-inch display.

It’s an unusual display; it is a 16:18 aspect panel with a native resolution of 2560×2880. It is “tall” in its normal orientation, but I’ve chosen to use it rotated which makes it look rather square (a great orientation for this display). A perfect screen for my use cases as a general UNIX system and web development workstation. (I do not game on my desktop Mac nor do I watch feature films, so a more traditional 16:9 aspect ration has little value to me here.) I’ve had this system up and running for two months now and I can say that, of all the displays I’ve ever used, this one is my favorite.

Doing research to spec out the screen for this iMac replacement, I encountered a large number of people lamenting the use of 4K displays with Macs, noting that the Apple 5K displays, with a 218 pixel/inch density, allow for a computationally easy halving of the native display resolution to achieve an ideal desktop rendering. A 5K Apple display has a native resolution of 5120×2880 and the default view mode is a “looks like” 2560×1440 desktop — razor sharp. Halving the native display resolution is easy peasy for GPU hardware — a small lift. This is, presumably, why Apple’s Retina displays are 5K rather than 4K. The thing with 4K displays is that in their typical native 3840×2160 resolution, they present the UI elements far too small, while the system-suggested half-resolution rendering is a sharp “looks like” 1920×1080 display where the UI elements appear too large — there’s too little desktop real estate.

The way around this is to have macOS “scale” the display to a more ideal lower resolution, but choosing that option in display preferences presents a warning: “Using a scaled resolution may affect performance.” What the OS does here is to scale up the chosen resolution to double height and double width (4x the pixels displayed) and then scale them back down to the display’s native resolution — 60 times per second. Indeed, this can be too much for certain older systems out there. But, as you will see, modern Macs should be able to handle the task just fine.

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Posted in Just Rambling, Macintosh | Tagged , | 34 Comments

An Apple II Tale Told Complete by the Late Tony Diaz

Posted on October 29, 2022 by Blake Patterson

I’ve been an active IRC users for nearly 25 years now, and for many of those years I was a denizen of the #a2c.chat channel on the irc.a2central.com IRC server. (IRC stands for Internet Relay Chat, a channel-based internet text chat system that was introduced in 1988.) That’s where I met Tony Diaz. Long a key figure in the yearly KansasFest Apple II gathering and possessing of an enormous personal collection (there were palettes) of Apple II-related hardware including the extremely rare, Tony was a fervent Apple II enthusiast and an absolute font of knowledge regarding all things Apple II. Regrettably, Tony died unexpectedly on October 27th near his home in Oceanside, CA. As I write this post, we have been without Tony for exactly one year — a year that the Apple II community has been bereft of one of its brightest stars, a friendly figure quick to lend a hand.

I met Tony in person but once, when he stopped by my home on a larger trip in order to pick up a NeXT 21-inch Color Display I had offered him and gave me a tour of the unicorn-rare prototype “Mark Twain” Apple IIgs he had packed in his PT Cruiser. It is IRC where I knew Tony, and we had many conversations over the year about this or that obscure aspect of Apple II computing. Having not only been an extreme Apple II hobbyist buy also having worked in Apple II-related and general hardware capacities, Tony had many stories to share. Here, a year after his passing, I share the one I found the most fascinating.

One day in early 2014 on IRC, I DM’ed Tony asking if he had any 65C02 CPUs and the proper ROMs lying around to enable me to upgrade an Apple IIe I had just acquired from eBay to an Enhanced IIe. I mentioned that I couldn’t even boot the Copy II Plus 9 disk I had on hand (a very popular copy program / system utility for the Apple II from Central Point Software) on that machine in its current configuration. Tony quipped that C2P 9 was junk anyway, and that I should use C2P 8. I asked after this, and he explained that C2P 9 was buggy, a total rewrite from the ground up due to the fact that the source code for C2P 8 had been lost. I asked if he knew the story behind that and, unsurprisingly, he was one of the few people in the world that did, and he proceeded to tell me the whole story.

What follows is a tale involving several amazing and unlikely finds coupled with a good bit of luck that, in the end, explains how that source code came to be lost, necessitating Central Point to entirely rewrite a core product. The story takes place in the early ’90s, when Tony was working at Alltech, a tech clearinghouse of sorts that sold old / hard to find items, much of it for the Apple II.

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Posted in Uncategorized | 8 Comments

Microsoft Sunsets Amiga’s Killer App: Internet Explorer

Posted on June 16, 2022 by Blake Patterson

It’s been nearly 27 years but, as life teaches us, all good things must come to an end. On June 15th, Microsoft ended support for Internet Explorer on all desktop systems, including its launch platform, the Commodore Amiga.

Or, so it would seem.

Microsoft tweeted the news yesterday from its official @MicrosoftEdge account. In the poignant tweet, the Redmond software giant bade farewell to its venerable web browser, stating with some sadness, “Now, it’s time to surf the big web in the sky,” while marking the woeful moment with an animated image of IE’s orbited-“e” logo, centered on a glowing blue screen which fades out to darkness on an Amiga 1000 computer.

As someone whose 23 year web development career has been made rather “challenging” on many occasions thanks to Internet Explorer and its many unfortunate virtues, this seems its perfect epitaph: A browser released in 1995 for Microsoft’s new, preemptive multitasking OS, Windows 95, memorialized on the screen of an Amiga, a graphics computer released by Commodore in 1985 that brought the first preemptive multitasking OS to the consumer market — ten years earlier. It wasn’t a DOS machine, it didn’t run Windows, and it never ran Internet Explorer.

RIP and good riddance, IE.

Posted in Amiga, Windows | Tagged , , , , , , , | 9 Comments

Fun With System Power Monitoring on the Apple IIe

Posted on June 4, 2022 by Blake Patterson
Apple IIe with Power Monitor

One of my favorite vintage systems in the “Byte Cellar” is my 128k enhanced Apple IIe. It is also one of the most frequently used; I fire it up for IRC or BBS sessions several times a week, and game and watch demos on it almost as often. The Apple II (a //c, specifically) was one of my very first home computers, and I have owned several different IIs over the years. As such, the Apple II platform holds a special place in my heart.

As far as I am aware, this Apple IIe has the original power supply in place. (I acquired this unit on eBay in late 2008 [gallery] and got my first IIe back in 1986.) Not too long ago, I purchased a replacement power supply kit from ReactiveMicro, but haven’t had a need to install it as yet, but I’ve been a little curious how well the in-place PSU is supplying power.

A few days ago I was browsing eBay’s Vintage Computing listings when I saw a modern device that could quell that curiosity. The device in question is the “Apple II+ IIe & IIGS Continuous Power Monitor Display,” which is an external 3D-printed box housing blue and red LED readouts for the Apple II’s +5, +12, -5, and -12 power lines that is attached to a simple breakout card that can be seated in any slot in the system. The unit gives a constant reading of the bus voltage levels while, its creator assures me, drawing a negligible amount of power from the system.

As I said, I was curious about the levels being output by my aged PSU, but that’s not why I bought this thing. I grabbed it because it looks all retro-tech “blinkenlights” cool. It reminds me of something that might have been part of David Lightman’s IMSAI 8080 setup [info via Wayback Machine]. I had two free slots (5 and 6) and I now have but one.

Have a look at the box for yourself. The embedded photo is a still of the scenedemo F15 D’Gamma Clone released by C64CD in 2016 and the video shows the system running the demo Plasmagoria, released by French Touch (who make quite a few demos for the Apple II) in 2015. Audio is being output via a stereo, 8-channel (6 voices, 2 whitenoise channels) Mockingboard “K” soundcard slotted into the system and the secondary, HDMI display is being driven by a VidHD board. A few voltage fluctuations can be seen in the video but it doesn’t get much more exciting than that, I’m afraid. My need-case for the power monitor is a little silly, but it feels fun!

Posted in Apple II | Tagged , , , | 1 Comment

A Colorful “Peek” at the Graphics Performance of the Apple II

Posted on March 12, 2022 by Blake Patterson

This week Apple held a special event in which it announced a variety of new hardware and services, chief among them being a new model in the Macintosh lineup, the Mac Studio powered by the equally new 20-core M1 Ultra SoC, and the new 27-inch 5K Studio Display. The impressively powerful Mac Studio takes the form factor of a “tall” Mac mini (kind of a IIsi to the mini’s Mac LC). As such, it has gained the nickname “Fat Mac” here and there on the forums. Those who’ve been following the Macintosh scene since the beginning will recognize the colloquialism as a dusting off of the nickname bestowed upon the Macintosh 512K, a model introduced several months later the release of the original 128K Macintosh.

Ahead of their special events, Apple publicizes them with imagery featuring an artistic take on the Apple logo along with slogan. The March 8th event was dubbed the “Peek performance” event and the associated imagery featured a set of rainbow-colored layers that convey a kind of tunnel effect. I love it when Apple brings out the rainbow of olde on their logo in any manner. This one looked quite nice, to me.

While I’m sure that there’s little hardware out there that could render such a vibrant and colorful image better than the Mac Studio with its accompanying Studio Display, I thought I would see how good a job one of the Mac’s grandfathers — my trusty 128K Enhanced Apple IIe — could do. And, so, I reached to Bill Buckel’s Bmp2DHR image converter, which I detailed in a post several years ago, to get the job done.

I grabbed the “Peek performance” logo from Apple’s website, adjusted and reduced it in size to a true-color, 640×480 pixel BMP image file (one of the acceptable input formats of the b2d program), and on the command line had the program convert the BMP to a 16-color Double High-Res image file, 16K in size. I then used Jason Harper’s ][GIF image viewer to display the image on my Enhanced Apple IIe equipped with a VidHD graphics adapter from John Brooks.

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Posted in Apple II | Tagged , , | 2 Comments

BBSing in the Snow Is the Best Way to Login

Posted on January 11, 2022 by Blake Patterson

I logged into my first dial-up electronic Bulletin Board System in the spring of 1986 at the house of a friend I was visiting. His family had an Apple IIe setup with an Apple Modem 1200, the kind that sat under a desktop phone, at one end of their den. He was a fairly avid BBS user and when I expressed an interest he logged in to a local BBS called OxGate and showed me around. (OxGate ran the RBBS software on a flavor of RCP/M, a multiuser CP/M-like operating system, and was located in Grafton, Virginia.) On his computer I setup an account and logged in. And I was off…

OxGate BBS login screen

A few months later, for my 14th birthday, I asked for and was given a Prometheus ProModem 1200A modem (thanks for the image, Tony) for my own IIe and was able to dial in on my own. Until I was able to have internet access at home (in 1994 via a dail-up PPP TCP/IP connection from a local ISP known as Widomaker over a Cardinal 28.8Kbps modem), dial-up BBSing was my favorite computer activity. That’s a solid 8 years.

It’s sad to recall just how quickly and completely I (we?) jumped from local BBSs to the web, when it became accessible from home, and didn’t look back. I finally did look back, but not for about 25 years.

When I think back on those days, I recall the most pleasant times on a BBS were rainy days — or, better, snowy days — when there wasn’t much you could do outside, but you could have a all kinds of fun discussing this or that in the message bases on the numerous BBSs in the local area code. (This was when it was all land lines and long distance charges were a thing). And most of what we discussed was the computers we were using to dial in on, and their particular attributes. Yes, BBSs were pretty geeky places.

On such days, looking out the window at the falling snow while posting online made the whole thing seem rather cozy.

And so, when the northern Virginia area was hit hard with a heavy snow last week and I logged into a few telnet BBSs on my current Apple IIe, I found myself, again, looking out at the snow and it kind of took me back to those loveliest BBSing days of the long past. Feeling that same winter cozy vibe, I took a photo and wanted to share it here to try and convey some of that “small world” magic that I’m sure more than a few readers once knew. (I used Paul Rickard’s WiFi232 serial-to-WiFi “modem,” which I’ve written about in the past along with a demo video, to get the IIe online.)

And, yes, BBSs are still a thing. These days they’re more telnet than dail-up based, but they’re out there and many of them are running on vintage hardware, interfaced this way or that to the ‘net.

If you’re interested in giving BBSing a shake, have a look at my little BBSing tips page and checkout the the Telnet BBS Guide for the long list of boards that are waiting for your “call.” Grab some hot cocoa and get online! Or, if you’d just like a quick glimpse, my BBSing photo gallery shows a variety of machines caught in the act.

Feels related, somehow:

Update: People have been asking about the sticker door. Here you go. Most of them came from Reddit’s r/Retrobattlestations competitions!

Posted in Apple II, BBS, Down Memory Lane, Just Rambling | Tagged | 7 Comments

Have a Helping of 8-bit Holiday Cheer! (2021 Edition)

Posted on December 24, 2021 by Blake Patterson
Pixellated 8-bit style plastic Christmas wreath

‘Tis the season, and that means it’s time to push out the eleventh annual Byte Cellar vintage computer Holiday demo roundup so everyone can feel that warm, fuzzy, pixellated holiday glow (which I think we could all especially use this year). With scanlines. Enjoy!

I’ve been a computer geek for a long time now, but I’ve been enjoying The Holidays even longer…

I got my first computer, a TI-99/4A, on Christmas morning in 1982. I was 10 years old and from that Christmas on, it was nothing but games and computer hardware that I wanted Santa to leave me under the tree. On through my teenage years, part of my ritual for getting into the Holiday spirit was downloading and watching Christmas demos on whatever system I had at the time. And, apparently I wasn’t alone in this, as Benj Edwards explains in his piece, “The Oddball, Nostalgia-Inducing Christmas Tech Art Of The 1980s And 1990s.”

Enjoying these demos is a personal tradition that I had, sadly, long left behind until 2010 (the year before I began writing these posts) when I was inspired to seek out the demo I remember best, Audio Light’s 1985 musical slideshow for the Atari ST. With the help of an emulator, I captured it to share online with readers. A year later, I fired it up again and watched it run through it’s 16-color, pixellated images and 3-voice musical holiday greetings. As I watched, it occurred to me that it might be nice to gather a few of the other demos I remember from the good ole’ days and present them here, in order to try to share some of the holiday cheer that they used to inspire within me.

The following list of demos ranges across a variety of platforms of olde and is sure to bring the warmth of the season to the hearts of any and all retrocomputing enthusiasts who behold it. Happy holidays, and I hope you enjoy the shows!

Be sure to also have a look at the dozens of demos gathered through the years in the 2020 edition, the 2019 edition, the 2018 edition, the 2017 edition and the 2011 – 2016 editions of this post.

Amiga — Shuffling Around the Christmas Tree by Desire (2021)
Commodore 64 — Christmas Mega Demo 2020 by The Santas (2020)
Atari ST — Merry Christmas by [??] (??)
Windows PC – Last Christmas by Royal Belgian Beer Squadron (2007)
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Posted in Holidays, Multi-Platform | Tagged , , , , , , , | 3 Comments

Parceiro: An Extraordinary Upgrade for Amiga 1000 Users

Posted on December 13, 2021 by Blake Patterson

In October 1985 I purchased the first Amiga sold in the state of Virginia. It was a transformative experience to have that level of technology on the desk in front of me as a young geek. The Amiga 1000 was miles beyond any other consumer computer available on the market at the time in several respects. It boasted preemptive multitasking, a palette of 4096 colors (at a time when EGA‘s 64-color palette was considered impressive), four channel stereo digital audio, and a custom chipset with a graphics co-processor that allowed for incredible on-screen animation. In fact, it was ahead of its time to such a degree that much of the tech press didn’t know what to make of it, and so it was largely considered to be an expensive game machine, sadly, which did not help its adoption (especially in the states). I loved that system, but software was very slow in coming for the new platform and after a while I put an ad in the newspaper, sold it, and moved on to another system (which was a routine I carried out for quite a few years). But, I never forgot the magic of that first Amiga.

Many years later (in 2009), despite having an accelerated Amiga 2000 on the desk, I acquired another Amiga 1000 system to try and relive that 1985 magic. I enjoyed the machine greatly, but even though I expanded it with 2MB of FAST RAM and dual SCSI hard drives, it was always difficult to load it up with programs and put it to use, as compared to my fully networked Amiga 2000 with its 68020 accelerator, ethernet card, SD-based SCSI hard drive emulator, and HxC2001 floppy drive emulator. The Amiga 1000 was more of an island and, as such, it saw little use.

Flash forward to late 2020 when I read a post by AmigaL0ve in which he described a new expansion device made specifically for the Amiga 1000. It was called the Parceiro (“parceiro” meaning “partner” in Portuguese) and offered a very impressive and useful 3-in-1 upgrade in a svelte side-expansion about the size of a Hershey bar — and all for a reasonable price. I ordered one immediately.

The Parceiro was created by Amiga hobbyist and (now retired) once-CIO of the United States Space Force, David Dunklee. An ardent fan of the Amiga 1000 and the landmark moment in computing history that it represented upon release, David designed the Parceiro to help bring this innovative system up to speed with other members of the Amiga family, for which upgrades are much more readily available.

The Parceiro consists of a single circuit board that happens to be festooned with printed references to some of the best pieces of old school nostalgia that will bring a smile to the face of anyone who was a child of the ’80s. Sitting in a removable plastic enclosure, it attaches to the Amiga 1000’s side bus-expander connector and offers the following features:

  • 8MB of auto configuring “FAST” RAM (the A1000 shipped with just 256K) with zero wait states (thanks to the use of SRAM rather than DRAM)
  • A front-facing microSD card reader supporting a 2GB card (bundled) formatted as a FAT32 volume allowing it to be read/written to on a PC or Mac for moving files, using live in an emulator, etc.
  • A Real-Time Clock (RTC) with onboard battery backup and a driver allowing it to be recognized my AmigaDOS at boot
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Posted in Amiga | 5 Comments

About the Personalized, Cut Wood Apple Logo Sign from 1984

Posted on July 26, 2021 by Blake Patterson

On Saturday KansasFest 2021 wrapped up and it was sad to see it end — what an amazing 48 hours it was! This was the second KFest I have attended (both virtual) and it was incredibly fun, just like last year. It is hard to believe I had never attended the event prior to the shutdown / need to go virtual, but my experiences during my virtual presence have certainly motivated me to soon show up in-person, and the hope is that next year everyone will be back at Rockhurst University and sharing in the event face-to-face.

One of the most enjoyable parts of the show for me was the Discord video chat that took place both Friday and Saturday evenings after the day’s sessions were done. I got to know many of the regulars a lot better during these fun group discussions where we chatted long into the night, sharing stories and showing off hardware, our pets (both organic and Commodore), and various other odds and ends. It was a late night and then off to sleep I went. 

The following morning my daughter, who had preceded my wife and me downstairs to eat breakfast, asked me if I had been up all night chatting with my “Kansas people.” I told her that, indeed, it had been a fairly late but fun chat and I proceeded downstairs to make myself some coffee. I then saw, on the kitchen counter what had clued her in. Through the course of the previous evening’s conversation, I had run down into the “Byte Cellar” to grab a few things to show on camera as the conversation ranged in topic hither and yon. When I signed off, I had left everything where it was and gone straight to bed.

On the counter I had left my NEXTSTEP v3.2 Academic Bundle (install floppies and all); a Disk ][ controller card for the Apple II that I asked its creator, Steve Wozniak, to sign during MacWorld Expo 2009; an airbrushed, cut wood rendering of my name beside the rainbow Apple logo of olde; and various other more modern gear that I used to take part in the online chat (M1 MacBook Air, iPad Pro, AirPods Pro).

Amused at the display I had left behind, I snapped a photo and tweeted it, later posting it to r/Retrobattlestations. Some conversation about NEXTSTEP and the Woz-signed card arose, but there seemed to be more interest in the wooden cut-out of my name next to the rainbow Apple logo. The item in question holds pleasant memories for me and has been with me nearly 40 years, so instead of responding to inquiries on twitter and Reddit, I thought I would talk a little bit about it here on the blog.

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Posted in Apple, Just Rambling | 1 Comment