22 June 2024, 18:38 | #5121 | |
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386 has a separate cache for paging (TBL cache with 32 entries), segment descriptors, and code queue (16 byte). 386 was geared for MMU operations. Last edited by hammer; 22 June 2024 at 18:43. |
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22 June 2024, 18:40 | #5122 |
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23 June 2024, 02:25 | #5123 | |
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Data Quest buyer's guide for 1993, page 49 68030-25 CQFP = 54.50 68EC030-25 PQFP = $34.00, higher clock speed variants would cost more. No MMU. 386DX-25 PQFP = $54.23 AM386-40 PQFP = $38.50 Includes MMU. For 68030-25, Motorola brain dead copies Intel's 386DX-25 prices. The majority of Intel CPU sales in 1993 were 486s. AMD dominates the fast 386 market. Motorola ignores AMD. 68040-25 = $227.75 68EC040-25 = $86.88, no MMU, useless for Amiga or any DMA'ed desktop computers. Another Motorola brain-dead move. 68LC040-25 is not listed. 80486DX-33 = $291.75 80486SX-25 PQFP = $88.87, functional for PC with DMA. Motorola's price policy sets up a situation for PC's Doom. |
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23 June 2024, 02:56 | #5124 | |
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I also have a 386SX-20 motherboard with cache RAM. It's an all-in-one design with onboard VGA, IDE, floppy, serial and parallel ports and PS/2 keyboard and mouse ports. It came from a Wang Alliance 750CD, which is a rare model quite unlike typical PC clones of the day. The inclusion of cache RAM is noteworthy because the 386SX CPU was specifically designed to work in existing 286 designs to keep the cost down. My board works well but is a bit problematic due the riser card and jumpers with unknown functions that make it difficult to try out expansion cards. That's why I recently purchased a more conventional motherboard for $180 (2nd attempt, the first one - though looking brand new - failed within a few minutes and is now dead!). 386SX boards are getting quite rare now. The attrition rate has been high, largely due to the dreaded nicad battery. Mine had the usual leakage, but luckily on this motherboard it was placed well away from critical stuff and so hadn't corroded away any tracks or gotten into the keyboard chip. |
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23 June 2024, 03:38 | #5125 | ||
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BTW the Mac didn't officially get virtual memory until 1991 with System 7. It required a 68030 or better with MMU and so didn't work with the Mac Plus, SE, Classic, Macintosh II or LC. Classic Mac OS memory management Quote:
Give me an OS that tells you how much free RAM you have and stops programs from trying to use more. Today we can easily put 128MB or more into any Amiga, so running out of memory isn't a problem for anything you are likely to do. My A1200 only has 32MB and that's plenty enough for all but the most taxing tasks that aren't necessary anyway (eg. unarchiving a huge file from RAM into RAM to avoid cluttering up the hard drive). |
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23 June 2024, 04:52 | #5126 | |||||
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23 June 2024, 05:27 | #5127 | |
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Yeah, it does kinda suck. Sorta. Maybe
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23 June 2024, 08:43 | #5128 |
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23 June 2024, 08:47 | #5129 | ||||
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Back then, they didn't had so much memory, and it would have helped to have an Os wth proper resource management and memory protection and virtual memory. Heck, the first two points would even help a lot today. |
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23 June 2024, 13:02 | #5130 | |
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The original Mac did have an implementation of swapping and used the concept of handles to allow the OS to load memory back to different addresses when needed so an MMU wasn't required. It did require applications to follow the rules though and probably only workable on a co-operatively scheduled OS which is why the Amiga didn't get it. Of course the Mac did eventually get Virtual Memory too, in System 7 and that did require an MMU. |
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23 June 2024, 13:24 | #5131 | |||
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From https://www.intel.fr/content/dam/doc...ual-report.pdf Intel reported the following 1. In 1994's fourth quarter, Pentium unit sales accounted for 23 percent of Intel's desktop processor volume. 2. Millions of Pentiums were shipped. 3. During Q4 1993 and 1994, a typical PC purchase was a computer featuring the Intel 486 chip. 4. Net 1994 revenue reached $11.5 billion. 5. Net 1993 revenue reached $8.7 billion. 6. Growing demand and production for Intel 486 resulted in a sharp decline in sales for Intel 386 from 1992 to 1993. 7. Sales of the Intel 486 family comprised the majority of Intel's revenue during 1992, 1993, and 1994. 8. Intel reached its 6 to 7 million Pentiums shipped goal during 1994. This is only 23 percent unit volume. For 68030-25, Motorola follows Intel's 386DX-25's price guide. Your "68k is a different market" counter argument is flawed. There's no need when desktop incompetent 68EC040-25's price has established the lowest-priced 68040-based SKU. http://kpolsson.com/micropro/proc1993.htm May 1993, Motorola announces the availability of 40 MHz 68040 processor. price is US$393 in 1000 unit quantities. June 1993, Intel adds more 3.3 volt 486 processors to its line: i486SX-33 (for US $171), i486DX-33 (for US$324), and i486DX2-40 (for US $406). Prices are in quantities of 1000. July 1993, AMD priced Am486SX-33 at US$185 in 1000 unit quantities. October 1993, TI486SXLC-33, TI486SXL-40, TI486SXLC2-50, TI486SXL2-50, with prices in 1000 unit quantities are, respectively, US$79, US$89, US$110, US$149. AMD 486DXL-40 processor for US$283 and Am486DX2-66 for US$463 in 1000 unit quantities. "Single source" sucks. Intel practically lost control of X86 cloners. Quote:
68040 MMU level of protection = 2. 80486 MMU level of protection = 4. 68040 has an 8-byte fetch per cycle from the instruction cache. 8 KB L1 cache is hard split between 4KB instruction and 4KB data. You can argue for split data and instruction cache assigned for two different MMUs. But, i80486 has a 16-byte fetch per cycle from the mix L1 cache. 8 KB L1 cache is mixed. 486DX4 has 16 KB L1 cache. 486 has 32 byte prefetcher before the L1 cache. 486 MMU is split between paging and segmentation units. The pro-68040 like https://www.nox-rhea.org/obsolete-ar...486-vs-mc68040 didn't factor in 486's 16 bytes fetch per cycle from the L1 cache! Pentium 60 and 66 were released in 1993. Facts: 68040 reached 40 Mhz with an unofficial 50 Mhz overclock. Reminder, Motorola lost the clock speed race multiple times. LOL Motorola wasn't a bastion for high clock speed. AMD used Motorola's copper-based process node and delivered a very high clock speed when compared to Motorola's PowerPC G4+. The Amiga platform didn't have mass production for 68040 on a similar scale as the PC's 486 counterparts. Weak mass production for the Amiga platform's 68040 socket infrastructure led to a very weak 68060 uptake. 486DX2 reached 66 Mhz in 1993. Later 486DX4 reached 100 Mhz. Quote:
Zorro III is inferior to VLB 33 Mhz with 486DX2-33/486DX2-66 or VLB-50 with 486DX50. https://en.wikipedia.org/wiki/NuBus Early Quadras only supported the 20 MHz rate when two cards were talking to each other, since the motherboard controller was not upgraded. This was later addressed in the NuBus implementation on the 660AV and 840AV models. Later Power Mac models adopted Intel's PCI bus. Doom... needs fast I/O and neither Apple Quadra AV nor Amiga Zorro III was designed like 486's VLB/PCI for 3D games! A1200's BlizzardPPC with BVision has PCI I/O, but that was released in 1998 when the gaming PC had a 64-bit 66 Mhz AGP in 1997. 486DX2-66 with VLB fast SVGA cards murdered Quadra 840AV in Doom. Like BlizzardPPC with BVision PCI, PiStorm-Emu68's VideoCore RTG bypasses the Zorro III (Super Buster) bottleneck. Last edited by hammer; 23 June 2024 at 14:53. |
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23 June 2024, 13:48 | #5132 | |
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Indeed, but at least you can use that power for other things, like gaming, Blender, etc. |
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23 June 2024, 15:11 | #5133 | |
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https://askubuntu.com/questions/4719...-use-which-one I do recall some problems with swap on Ubuntu in past and zswap significantly improved overall system behavior. |
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23 June 2024, 15:16 | #5134 | |
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Example https://ftp.fau.de/aminet/docs/rview/GigaMem2.0.txt I purchased low-cost stock A1200 during the COVID-19 lockdown and the 68EC020-14 and PIO IDE was limiting coming from A3000's POV. I purchased AmigaKit's 8 MB RAM card and TF1260. Without TF1260 or PiStorm32, I would have purchased TF1230. My argument for "the need for speed" with A1200's compute power stems from my A3000's familiarity, but I'm also aware of the mass production models to sustain Commodore. I'm digging into the cost structure for A1200 and investigating the Psygnosis vs Ali issue. |
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23 June 2024, 15:39 | #5135 | ||
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24 June 2024, 07:48 | #5136 | |||
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Swapping from disk was used on the Amiga, in the form of overlays. Deluxe Paint did it. Shared libraries etc. also have a sort of 'swapping' where unused resources can be be expunged from memory and then reloaded when opened again. Quote:
Not only did it require programs 'following rules' (which Amiga OS also requires) it limited the instructions you could use and/or made the code messy and inefficient. Even worse, you never knew when the OS might decide to compact memory, which could take quite a while. This was incompatible with an OS that was supposed to be capable of real-time animation. Quote:
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24 June 2024, 08:14 | #5137 | |
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I wish that worked, but it doesn't on 32 bit machines (even after patching it to fix the bad instruction that barfs on 020+ CPUs).
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I believe EMU68 can allocate up to 2GB of RAM to the Amiga. Should be enough... Imagine if someone told you in 1993 that in the future your A1200 could have 2GB RAM, ultra-high resolution RTG with 3D, and an 800 mips CPU, all for under AUD$300. You wouldn't believe them. |
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24 June 2024, 08:25 | #5138 | |||
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24 June 2024, 08:38 | #5139 | ||
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The proximate reason Macs are so slow running Doom is that they don't have a 320x200 video mode. Their video hardware is so crude that they can't optimize and have to write 4 times more bytes to get the same screen size. So much for chunky pixels! BTW Doom runs silky smooth on my A600, even in 640x480. That's what a Vampire does for it. And yet, I still enjoy playing it on my A1200. Quote:
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24 June 2024, 09:11 | #5140 | |
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2. QuickStart's A3000 with Kickstart 3.1, 2 MB Chip RAM, 8 MB Fast RAM 3. DF0 = WB 1.3.4 4. DF1 = WB 1.3.4 Extra 5. Run "NoFastMem" 6. Run BasicDemos' Music demo. With active fast memory, Amiga Basic has a "File not found" error with the same Music demo. ---- With Stock A1200 with 2 MB (Zorro II) Fast RAM, Amiga Basic's music demo works. Last edited by hammer; 24 June 2024 at 09:25. |
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