On 13 January 2014 17:35, emanuel stiebler <emu at e-bbes.com> wrote: Ah ha! I was going to link to that in reply to Ethan's comment myself. It looks like a very interesting design. I shudder to think what it would have cost in the early-to-mid 1980s, though. The QL was a very badly compromised design, sadly. A fascinating machine, but almost every single design decision in it was wrong, in hindsight. IMHO, the QL done right - a 68000 home computer, built to a strict, tight budget, using COTS parts and a largely COTS software stack - was the Atari ST. The standard 8-bit sound chip, a standard PC floppy controller, (I believe) PC-derived graphics chips etc. - and it was still nearly twice the price of the QL at launch. And Atari's sort of incremental launch strategy - the first public prototypes with 256kB of RAM, the soft-loaded OS, the external transformer and modulator and floppy, all gradually built in as the machine grew into its final form... a good, sensible, if merely pragmatic process. As opposed to Commodore's big-bang Amiga 1000 which was too expensive for almost anyone at first, so that real mass market sales had to wait on the cheaper, cut-down Amiga 500. It's no irony that Tony Tebby eventually took the QL's OS onto the ST as SMS2 and eventually SMSQ/E. -- Liam Proven ? Profile: http://lproven.livejournal.com/profile Email: lproven at cix.co.uk ? GMail/G+/Twitter/Flickr/Facebook: lproven MSN: lproven at hotmail.com ? Skype/AIM/Yahoo/LinkedIn: liamproven Tel: +44 20-8685-0498 ? Cell: +44 7939-087884

On 2014-01-13 12:25, Ethan Dicks wrote: I talked to this guy, and he is happy with it as it is. Took him a while to do it (he did all the schematics/layouts/software himself), so he is not eager at the moment to change it to the 16bit version. There is actually some discussion on the forum of this board. Cheers

On 1/13/14, 2:57 PM, Ethan Dicks wrote: I believe the 68HC000 can dynamic size down to 8-bits, so that's a more available solution for 8 bit designs. I think I did that once.

On Mon, Jan 13, 2014 at 6:20 PM, Eric Smith <spacewar at gmail.com> wrote: Of all of those, I only know a little about the 68EC000 but never worked with it. ISTR hearing it was popular in washing machine controllers, but that could be a fuzzy memory. I haven't kept up with what's in production and what is not. There are so many MC68K-family CPUs out there that any project I'd tackle wouldn't make a dent in the supply. I have a crate of 64-pin DIP MC68000P (plastic) parts if anyone is shopping - enough for two lifetimes. -ethan

I've wished more CPUs were like that, ie, had no minimum clock frequency. It makes some kinds of hacking-around easier. (I've never really understood why any CPU would have a minimum clock frequency, short of things like on-die clock multipliers.) /~\ The ASCII Mouse \ / Ribbon Campaign X Against HTML mouse at rodents-montreal.org / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B

On Jan 13, 2014 8:47 PM, "David Riley" <fraveydank at gmail.com> wrote: The MC68SEC000 is a drop-in replacement for the MC68EC000, but not necessarily for the non-EC parts, because the EC and SEC use two-signal bus arbitration (BR/BG) like the 48-pin MC68008, rather than three-signal (BR/BG/BGACK) like the MC68000, MC68HC000, and MC68HC001. And that it's not available in all of the packages the MC68000 was.

On Tue, Jan 14, 2014 at 10:28:20AM +0000, Peter Corlett wrote: Just curious, were the problems related to hardware or software relying on cpu timing and the likes?

On Thu, Jan 16, 2014 at 12:08:43PM -0500, Sean Conner wrote: In the case of that specific device, they obtained the 14MHz clock for the 68010 by doubling the 7MHz clock that drove other system components. A hack that breaks all sort of things, in other words. The most obvious casualty was trackdisk.device, whose waits for floppy drive heads to settle had halved and it caused all sorts of disk problems. The widget came with a custom bootblock that fiddled with trackdisk.device's timings, but it was still not satisfactory as much of the software I ran already had its own custom bootloader. Presumably they saved a couple of quid on 74-series chips with that design. I doubt they saved money overall with the number of returns they must have had. The Amiga's exec.library abstracted the differences away. Under the hood, although the default was the plain 68000, it probed the CPU and switched in new functions to provide a CPU-neutral API. As far back as Kickstart 1.2 (which was what, 1987?) it understood the 68000 through 68020. I routinely booted Kickstart 1.3 on my 68040 box to run the more recalcitrant software, and it all worked. To the probe code, a 68040 looks just like a 68020 without FPU or MMU, and it turns out to emulate that combination nicely! The 68010 provided some minor improvements, both in performance and functionality. Unless one was playing silly buggers with timing loops, there were no real surprises except that code tended to execute slightly quicker. Generally it wasn't worth it though, and one was better off going for the 68020. It was a reasonably elegant and orthogonal processor. Howerver, I've finally realised I'm not smart enough to be a hardcore assembly-language guru, so wandered off and found other niches. I'm probably a heretic here, but x86-64 isn't actually all that bad once it's in long mode. All of the segmentation hacks and special-purpose registers pretty much sod off. There is some lack of orthogonality, but it doesn't seem any worse than the 680x0's occasional distinction between D and A registers.

On Thu, Jan 16, 2014 at 12:08 PM, Sean Conner <spc at conman.org> wrote: In the case of the Amiga, dropping in a '010 was fine from the OS standpoint. The calculator app that came with AmigaDOS 1.0 and 1.1 used a DBcc instruction and threw an error. There was a simple error trap handler one could install. Starting with AmigaDOS 1.2, no component of the OS flinched if you had a '010, but some games still used privileged instructions. I had an 8MHz 68010 in my A1000 for most of the time I used it. I got a real-world speed boost of about 5%. I also originally had a non-DMA disk interface, so the transfer loop was greatly enhanced by the 1-instruction cache, so I liked it, and the chip cost less than $20, so it was the cheapest way to enhance an A1000 (or A500). I never tried it in any other machine, so I can't speak to compatibility issues, but because instruction restart really worked, the 68010 _was_ used for early UNIX machines where a simple 68000 system wouldn't have worked (there were some elaborate schemes to support demand-paged VM with a real 68000, including having two 68000s and letting the second one take over to handle things when the first page-faulted). One of my favorite architectures ever. I feel privileged to have made my living for several years writing code for it. -ethan

On 01/16/2014 04:52 PM, Eric Smith wrote: I remember talking with a Moto fellow at some early 80s Wescon, that the business of virtual memory and the then-very-new 68000 was getting to be one of the most often-asked questions by engineers wanting to put the chip with a real supervisor mode and a bus error trap--and having to tell them that, no, you couldn't do it. (Although there *were* workarounds--you could run two 68Ks, out-of-phase with one another, using one to "test the water" a bit ahead of the other--or you could restrict the instructions used by programs. Neither was really satisfactory, but there were products using them). I remember feeling the excitement--and the disappointment. I still have my freebie manual from Wescon. Still, it was a nice CPU and we did work up a wirewrap test version that seemed to run well. --Chuck

On Thu, Jan 16, 2014 at 7:52 PM, Eric Smith <spacewar at gmail.com> wrote: My bad. You are correct. As you say. -ethan

On 13 January 2014 19:25, Ethan Dicks <ethan.dicks at gmail.com> wrote: It seems to me that he was trying to make the ultimate 8-bitter, in a way. *The* 8-bit sound chip - no less than 2 of them, for stereo, magnificently self-indulgent - and what might be the ultimate COTS 8-bit graphics chip, the one from the MSX2 machines IIUIC. And then what is, one could argue, the most powerful CPU that one can put on an 8-bit bus. So, yes, it's constrained, very constrained, but if he moved from a 68008 to a full 68000, then it would be a 16-bit machine, and suddenly that choice of sound and graphics chip would make no sense at all. And if you wanted better 1980s graphics & sound chips for a 68000 machine, well, it's been done, the job's been taken - that's an Amiga, really. And the Amiga is of course a grown-up computer with a grown-up multitasking GUI OS, whereas the Kiwi boots into a ROM BASIC like a proper 8-bitter. :-) Sadly, the homepage for said ROM BASIC is offline and has been since I first learned of the machine, months ago, AFAICT - so I know nothing about it. Shame; it sounds very interesting. In its way the Kiwi "makes sense" to me. The QL was an attempt to make a super-cheap 16-bit home/business computer using Sinclair's cut-costs-to-the-bone-and-then-sculpt-the-damned-bone-down approach. Result: too compromised to be very useful. It was cut down too far; as a 16-bitter, it was so crippled it was almost useless. And let's face it, the main use for 1980s home computers was games, and the QL was a rotten games machine - but it was also a rotten business computer, too. The right way to do a 68000 home computer on a tight budget was what Atari was forced into doing when all its chip designers quit and went off to make the Amiga. In response, the company did a quick-and-dirty rival box with no fancy chips at all and a bought-in OS, but it was good for the money. The "Jackintosh" really /was/ power without the price. So if the 68008 was too compromised to be the basis of a useful 16-bit home computer, what's other ways are there to go? The Apple ][gs is one direction: take an old 8-bit design and update it with a hybrid 8/16-bit chip. Interesting approach, *far* more elegant than the Commodore 128 - but despite good graphics, great sound and an interesting OS, it was a very expensive and deeply compromised machine that wasn't really any competition for the ST or the Amiga. (But sadly *was* enough competition to threaten the Mac, so it got killed. Great shame.) If Sinclair had tried to update the ZX Spectrum, I suspect the result would have been similar. The Spectrum *was* cheap & terrible, really, but then, it was affordable and all home computers of the early 80s were pretty terrible to some degree - or they were ludicrously expensive. (Or both.) A more expensive Spectrum would have still been very limited, but in direct competition with the more-expensive, less-terrible 8-bitters. (If I had a time machine, I'd go back and get Sinclair to use the ULA update the Spectrum needed: less-terrible still-cheap-and-simple graphics.) But the "dream machines" of the early-to-mid 1980s were ludicrously dear: the Elan Enterprise, for example. Later, there were weird bodge-up "upgrades" - the C128, because obviously what C64 owners wanted was a Z80 and CP/M. (!) Then there were things like the ][gs and later still the MGT SAM Coup? - a gorgeous machine, but very underpowered compared to an Atari ST. So if you want to make a sort of ultimate, money-no-object 8-bit without crossing the line into a full 16-bit machine with a GUI, lots of RAM, multitasking, etc., then you would want: * great sound - that means the CBM SID chip * great graphics - lots of colours, sprites etc., no attribute clash, and at TV resolutions * lots of RAM in a flat memory space, no bank switching - say 1MB * a faster CPU and screw backwards-compatibility * a decent ROM BASIC * a floppy interface That, it seems to me, is what the Kiwi is. -- Liam Proven ? Profile: http://lproven.livejournal.com/profile Email: lproven at cix.co.uk ? GMail/G+/Twitter/Flickr/Facebook: lproven MSN: lproven at hotmail.com ? Skype/AIM/Yahoo/LinkedIn: liamproven Tel: +44 20-8685-0498 ? Cell: +44 7939-087884

On 13 January 2014 22:11, Ray Arachelian <ray at arachelian.com> wrote: Now that you mention it, ISTR something along those lines myself. There was a great article by Bil Herd about building the C128 on Hackaday recently: http://hackaday.com/2013/12/09/guest-post-the-real-story-of-hacking-togethe… AFAICS it doesn't mention this function of the Z80, though. Bil happily and confidently claims that it was: "the last mass production 8 bit computer and first home computer with 40 and 80 column displays, dual processors, three operating systems, 128k memory via MMU and one heck of a door stop." It wasn't the 1st 8-bit to break the 64kB barrier (Memotech? BBC with sideways RAM?) and that it was the last 8-bit micro (it wasn't - as the 1st commenter points out, the SAM Coup? came considerably later). But still, a remarkable machine. -- Liam Proven ? Profile: http://lproven.livejournal.com/profile Email: lproven at cix.co.uk ? GMail/G+/Twitter/Flickr/Facebook: lproven MSN: lproven at hotmail.com ? Skype/AIM/Yahoo/LinkedIn: liamproven Tel: +44 20-8685-0498 ? Cell: +44 7939-087884

On Mon, Jan 13, 2014 at 3:00 PM, Liam Proven <lproven at gmail.com> wrote: I think the one thing that killed the IIgs for me is the S-L-O-W floppy disk performance. It is dreadfully slow, so much so that it makes the rest of the system seem bogged down. Otherwise it seems to be a nicely capable machine.

On 13 January 2014 19:30, Ethan Dicks <ethan.dicks at gmail.com> wrote: Not that I can actually identify almost any of those add-ons, I'm sure that's still a system that would have had me drooling 25y ago. :?) [Nod] There was another factor with the delays & waiting for sensible pricing, though... Rival products. The Amiga and ST were roughly contemporaneous. The Amiga was undoubtedly the superior machine, but the ST was much more usable with a single floppy drive and 512kB of RAM, a hair faster and "good enough" for a lot of people. As for me, it was about 1989 or 1990 before there was any chance of me affording such a machine - and by then, I could get a used Acorn Archimedes. I wasn't a gamer so I didn't care about the Miggy's graphics - at heart, its strength were moving graphics and genlock, stuff I didn't care about. I'm also not a musician so I didn't care about its sound abilities either. The ST would have been more than good enough for me in either department. But by the time I could afford to spend ?800 on a computer, I could get a RISC workstation with a 20MB hard disk for that money. No fancy animated graphics facilities but a very good display chip, also capable of 4096 colours; decent sound; a multitasking GUI-based OS in ROM... and about 4x faster than a 68000, IIRC. Oh, and as a (very amateur) BASIC programmer, it also had the best BASIC interpreter in the world at the time. The BASIC didn't multitask (like the QL's, actually) but then again as my main interest was fractals, I didn't want that to multitask - I just wanted the maximum possible speed. Looking back, RISC OS seems very limited today. OK, not as limited as TOS/GEM ;?) but quite rudimentary compared to Amiga OS, I guess. But it was something small enough and manageable enough for a kid to understand and master. That's certainly not true of Linux (or Windows or Mac OS X) today. And RISC OS is still around, still in active development (just about), and can be used on a modern network (just) and to access the Internet and WWW (just). The same is true of the Amiga OS, of course, while TOS/GEM is to all intents and purposes long-dead. Saying that, TOS/GEM is FOSS now and I was playing with this quite impressive Live CD recently: http://aranym.org/livecd.html -- Liam Proven ? Profile: http://lproven.livejournal.com/profile Email: lproven at cix.co.uk ? GMail/G+/Twitter/Flickr/Facebook: lproven MSN: lproven at hotmail.com ? Skype/AIM/Yahoo/LinkedIn: liamproven Tel: +44 20-8685-0498 ? Cell: +44 7939-087884

On Mon, Jan 13, 2014 at 06:53:06PM +0000, Liam Proven wrote: [...] Have a look at https://en.wikipedia.org/wiki/Atari_ST#Technical_specifications According to that page, about half of the chips were custom, including the video hardware. Why they bothered building custom hardware for such pedestrian video when there was surely suitable COTS parts is anybody's guess. The ST's floppy controller is the COTS WD-1772, and that series of controllers was extremely popular in a lot of 8 bit machines. The 1770 is a familiar number to me as being the one they had to bodge into the BBC Micro because supplies of the controller it was designed to use had dried up. The PC uses the 8272A or compatible, and the less said about that dog's breakfast, the better. ISTR that disks written on the two controllers are slightly incompatible with each other, but mercifully I have recycled those particular neurons. (And it pales into insignificance compared to trying to read *Amiga* disks.) Its sound was basically the Yamaha AY-3, a chip that as pretty impressive for its time and again appeard on many eight bit machines such as the BBC Micro (again) and newer ZX Spectrums. Sadly, the chip's time was the early-to-mid 1980s, rather than 1989-1990 when the ST was really starting to gain traction in the UK.