[HN Gopher] Second Revision of 6502 Laptop
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Second Revision of 6502 Laptop
Author : uticus
Score : 110 points
Date : 2026-04-03 13:06 UTC (4 days ago)
(HTM) web link (codeberg.org)
(TXT) w3m dump (codeberg.org)
| ksimukka wrote:
| Amazing
| artemonster wrote:
| Imagine in steampunk fashion wed get an alternative future
| timeline where computer tech froze in 80s due to some physical
| limitation that prohibited shrinking transistors. all typical
| laptops would have same config as this awesome project. what
| would the society become?
| sublinear wrote:
| Laptops would be a lot less common. If computers were stuck in
| this era for that long, fewer people would be interested.
| Prices would be high.
| voidUpdate wrote:
| I believe the actual silicon of a 6502 is much smaller than the
| DIP package, so even if we couldn't shrink the silicon itself
| much more, you could just take up more space inside the
| package, and use a package that has more pins in it, like
| current CPU designs. You would probably hit a bottleneck at
| some point since I believe the speed of light is a problem for
| processing speed at some point, but then I'd expect we'd just
| go into massively parallel systems, with multiple cores acting
| somewhat individually
| veltas wrote:
| Okay what if something else had prevented something better
| than a 6502 being mass market available?
| voidUpdate wrote:
| the 6502 package would probably shrink to use something
| like a BGA package, and you could probably make some kind
| of "multicore" system using 6502 processors. I'm not
| knowledgeable enough to say how feasible that would be, but
| you could probably use something with shared memory regions
| to pass data between them and run code in parallel.
|
| If you are absolutely limited to 6502 DIP chips, there
| would probably be more prevalence of large mainframe
| systems and single 6502-based "terminals"/"thin clients".
| The mainframes could use systems similar to the Transputer
| or the Connection Machine to use large amounts of
| (comparatively) low-power processors to make a single, more
| powerful computer. They both used custom processors, with
| the Connection Machine in the early 80s and the Transputer
| in the late 70s. You could probably reasonably easily
| create a "graphics card" style system, comprised of many
| 6502 cores in a SIMD configuration.
|
| I don't know how easy it would be to implement wifi or
| ethernet with only 6502 chips, so communications with the
| mainframe might be quite slow
| forinti wrote:
| I was thinking lately about how much memory you could handle on
| a 6502. The BBC Micro had a 16KB block of RAM paged between up
| to 16 ROMs/RAM but if you could have 256 banks you could do
| 4MB. One problem is that that would require a very large PCB.
| Another problem is that the OS searches for commands on all the
| ROMs and this would become slow for so many banks; one solution
| would be to limit the ROMs to the first few banks and let the
| rest be RAM.
|
| It could be useful for some sort of minicomputer for business
| applications.
| Joker_vD wrote:
| Depends entirely on what banking scheme you use. Nothing
| stops you from adding e.g. an 8-bit banking register (even
| two of them, one for instruction fetches, another one for
| normal memory reads/writes) to serve as bits 23-16 for the
| 24-bit memory bus. That's what WDC 65C816 from 1985 does, but
| it also goes full 16-bit mode as well.
|
| And if you have a 16-bit CPU, you can do all kinds of silly
| stuff; for instance, you can have 4 16-bit MSRs, let's call
| them BANK0-BANK3, that would be selected by the two upper
| bits of a 16-bit address, and would provide top 16 bits for
| the bus, while the lower 14-bits would come from the original
| address. That already gives you 30 bits for 1 GiB of
| addressable physical memory (and having 4 banks available at
| the same time instead of just 2 is way more comfortable) and
| nothing stops you from adding yet another 4 16-bit registers
| BANK0_TOP-BANK3_TOP, to serve as even higher 16 bits of the
| total address -- that'd give you 16+16+14 = 46 bit of
| physical address (64 TiB) which is only slightly less than
| what x64 used to give you for many years (48 bits, 256 TiB).
| forinti wrote:
| I was trying to get a grasp on what would be pratical.
|
| Even 4MB would take you hours to load from floppies with a
| 6502.
|
| Terabytes with a 68000 would also be impractical.
| Joker_vD wrote:
| > Even 4MB would take you hours to load from floppies
| with a 6502.
|
| Depends on your clock. Also, you could use some dedicated
| hardware, like a DMA controller e.g. 8257, or 8237. From
| 8257's datasheet: Speed
| The 8257 uses four clock cycles to transfer byte of
| data. No cycles are lost in the master to master transfer
| maximizing bus efficiency. 2MHz clock input will
| allow the 8257 to transfer at rate of 500K bytes/second.
|
| and I recall 8237 could do even better, if wired and
| programmed properly.
| bluGill wrote:
| Hard drivers were available for the 6502. They were
| expensive ($10k for a 10MB drive as I recall prices came
| down a lot, but never affordable in the 1980s)
|
| Processing terabytes with a single CPU was impractical,
| but you could in theory connect it.
| einr wrote:
| The Commodore REU (RAM Expansion Unit) architecture for the
| C64/C128 allows for up to 16 MiB - 256 banks of 256 addresses
| in 256 pages.
|
| Due to the lack of support hardware in the C64 (no hardware
| RAM bank switching/MMU) this memory is not bank switched and
| then directly addressable by the CPU, it's copied on request
| by DMA into actual system RAM. But in some sense, a C64 with
| a 16 MiB REU is a 6502 with 16 MiB RAM.
|
| But yeah, you want CPU addressable RAM with real bank
| switching. You couldn't really do 16 MiB, you wouldn't want
| to bank switch the entire 64 KiB memory space. The Commander
| X16 (a modern hobbyist 6502 computer) supports up to 2 MiB by
| having hardware capable of switching 256 banks into an 8 KiB
| window (2 MiB/256 banks = 8 KiB).
|
| Let's say you design something with 32 KiB pages instead --
| that seems kind of plausible, depending on what the system
| does -- you could then do 256*32 = 8 MiB and still have 32
| KiB of non-paged memory space available. I think this looks
| like just about the maximum you would want to do without the
| code or hardware getting too hairy.
| bluGill wrote:
| I know someone who - in the 1990s had 5MB connected to his
| Atari. He had two different expansions, and used all the
| memory for a RAM disk, as a result his BBS was the most
| responsive remote system I've ever used - including ssh to
| the server under my desk (open question, was it really or is
| this nostalgia?).
| flenserboy wrote:
| Speed certainly wouldn't be there, but capabilities would.
| Plenty could get done on those old machines -- most of it had
| to do with programmers having the imagination & skill to be
| able to shoehorn their ideas into spaces they weren't meant to
| be crammed into.
|
| One memory this project brought to mind for me was a hack I
| came across which allowed simultaneously running DOS 3.3 &
| ProDOS on a 128k Apple II, giving each 64k (well, a little less
| due to overhead) & a way to switch between the two with a
| simple command. Two programs couldn't run at once, but one
| could step between the two OSes to run programs made for each
| pretty seamlessly. If this sort of thing was possible on basic
| consumer hardware, ten or twenty years of development would
| have led to many far more interesting & useful things.
| artemonster wrote:
| nah, something like LLMs wouldnt be possible due to sheer
| power consumption - abstract (FL)OPs/uW is billions worse
| than modern tech. I used claude to make me back of a napkin
| calcs - single LLM prompt in 6502 era tech would be over 3k
| Eur vs fraction of a cent today, DISRECARDING WALL TIME
| (which is ridiculously impractical)
| zabzonk wrote:
| > Imagine in steampunk fashion
|
| See The 8-bit Guy regarding what the world would be like if we
| were still limited to vacuum tubes:
| https://www.youtube.com/watch?v=mEpnRM97ACQ (video)
| throwaway27448 wrote:
| Isn't this basically the idea behind collapse os? Chin up! That
| could _still_ be our future.
| singleshot_ wrote:
| Apple XXVgs and Amiga 15,000, I'm digging this alternative.
| pdimitar wrote:
| I was writing algorithms to find prime numbers on a 6502 some
| 31-32 years ago and I hold dear memories.
|
| There have been multiple initiatives to remake a 6502-based
| computer. My today's self does not appreciate the 8-bit
| limitations however; artificial and not limiting in the way that
| sparks creativity. I'd much rather work with a 32-bit micro PC (I
| believe they're called micro-controllers?) and be able to address
| more memory and then try to minimize its use, rather than being
| stuck at 8/16-bit addressing forever.
|
| But every time I see a 6502 post, I get a tinge of longing. :)
| bullen wrote:
| What is the GPU? Some sort of FPGA?
|
| Edit: Also picture missing from the page, the keyboard:
|
| https://codeberg.org/TechPaula/LT6502b/src/branch/main/Image...
|
| Edit2: Found a few suspects in BOM: ATF1508AS-7AX100, ATmega88PA-
| AU, ATmega644P-20A
|
| Would love to know what each will do!?
|
| The previous one hints a bit:
| https://codeberg.org/TechPaula/LT6502
|
| A blog entry: https://www.maddox.pro/?p=414
| mghackerlady wrote:
| I would love to see a future z80 version so I can run C/PM
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(page generated 2026-04-07 23:02 UTC)