16-bit Processors

8Bit, 16bit, Atari, Commodore, Apple, Spectrum, Acorn, TSR. All now defunked computer systems.

16-bit Processors

Postby RoboCop » Sat Apr 09, 2022 3:58 pm

In this topic, I will be explaining two 16-bit processors as well as some of their newer generations but only a little on their 32-bit successors. The two 16-bit processors that I will be explaining are the Motorola 68000 and the Intel 8086. They are some other 16-bit processors that exist but didn’t compete very well, such as the Zilog Z8000 - which was the new 16-bit upgrade to the popular 8-bit Z80. However, the Z80 can still be used for 16-bit machines, like the Sega Mega Drive (Genesis for Americans) that use the Z80 as a co-processor for sound and backwards compatibility for the Master System. The same applies to the SNK Neo Geo console for the Z80 used as a sound co-processor. If you want to know more about the Zilog Z80 and some other 8-bit processors, you can find out more here: viewtopic.php?f=13&t=6737

Before I explain those two processors, 16-bit machines started to dominate in 1984 during the aftermath of the 1983 Video Games Crash, along with when the founder of Commodore - Jack Tramiel left and reincarnated Atari Inc. as Atari Corporation in 1985, and Apple’s co-founder Steve Jobs who left in 1985 and then founded NeXT Inc. Not to forget that those computer companies began to develop some business vendettas, such as Atari Corporation Vs Commodore occurred when Jack Tramiel and some of his former executives and his sons left Commodore. Jack Tramiel had some major disagreements with some of the board members and with Commodore’s investor Irving Gould. Tramiel and Gould didn’t exactly get on like a house on fire. Steve Jobs was forced to leave Apple in 1985 when Apple’s former CEO, John Sculley who joined Apple in 1983 asked Jobs to leave. The reason behind Steve Jobs’ departure was due to the original Macintosh's early failure and that it didn’t compete well with the IBM PC ATs as well as the Atari ST, which the ST was more affordable and had colour compared to the Macintosh 128K.

Intel 8086:-
The i8086 was created as a 16-bit processor and was launched in 1978.

Motorola 68000:-
The M68000 is slightly more unique compared to the i8086 as it contains a 16-bit internal data bus, but also a 32-bit instruction set along with 32-bit registers. Although its newer generations of the 68000 are 32-bit processors; like the 68020, 68030, 68040 and the final M68k family generation - the 68060. The 68000 was commonly used for 16-bit computers, game consoles as well as arcade game cabinets from around 1984 until the mid-1990s. Even quite a lot of 16-bit games and applications were coded in 68000 assembly code for the Motorola 68K as programmers moved on from the inferior BASIC dialects, but some other programs were also coded in Pascal, C as well as C++ and more.

Also, I won’t be displaying nor explaining too much on a lot of 16-bit machines - especially ones that were a commercial failure and didn’t compete very well. So first off is the IBM Personal System/2:-

Now I know that there are over dozens of various IBM PCs like the AT and XT, but there is a reason why I’ve picked the Personal System/2 and focused on the Intel 8086 models. The IBM Personal System/2 or IBM PS/2 was launched in 1987 and allowed support for PC DOS, OS/2 as well as Windows version 2, 3.x (including the Windows NT 3.x) operating systems for later models. The IBM PS/2 25 models were built as All-in-one computers using an Intel 8086, whilst the PS/2 30 models were desktop computers. IBM also offered 32-bit processor versions like the PS/2 70 and 80 models that contain an Intel 80386DX CPU. The intriguing part about the IBM Personal System/2 is when the VGA and Keyboard & Mouse ports first appeared in 1987, which is when VGA ports became popular and ubiquitous for modern PCs until HDMI gradually replaced VGA. PS/2 ports for Keyboards and Mice (hence the name PS/2) also became ubiquitous, especially for some or most latest PC motherboards, that still use those PS/2 ports for several reasons. If you want to know more about PS/2 ports and learn its benefits, you can find out more here:-
Code: Select all
https://apg-clan.org/showthread.php?69320-USB-Vs-PS-2-Mice-and-Keyboards


Pros:-
>> Even though those IBM PS/2 machines were expensive but at least they had offered low-end models like the 30 model for a minimum of $2,299 compared to the more powerful 80 models for $6,999
>> IBM introduced the iconic Model M Keyboard which was comfortable to type
>> The 50 model had a 1MB RAM and supported 3.5-inch floppy disks formatted for 1.44MB, which was near twice as big compared to Atari ST and Amiga formatted floppies


Cons:-
>> The 30 models were powered with the slower Intel 8086 which contains fewer clock cycles and transistors compared to the newer i80286 and the Motorola 68000
>> Most of the IBM PS/2 machines weren’t affordable for many consumers with a low income
>> IBM PS/2 portable models were extremely expensive near $15,000 and quite fragile - especially for the Hard Disk Drives


Improvements that should have been made:-
>> Well not a lot apart from making very low-cost computers?


Apple Macintosh (128K):-
The Apple Macintosh 128K first appeared in computer markets in 1984 priced at $2,495 to eventually replace the expensive Apple Lisa and the 8-bit powered Apple II. The Mac wasn't Apple's first 16-bit computer as the Lisa first appeared in 1983 and contained a Motorola 68000 clocked at a lower 5 MHz. Of course, the 128K model wasn't enough for 128KB of RAM, which was why Apple had to create and develop the 512KB RAM model in 1985. But neither of those Macs supported colour displays, which was a big disappointment. The Macs had eventually moved on to using the newer 68030 and with a colour display - like the Mac Colour Classic launched in 1993, priced at $1,400 slightly lower than the original Mac. And Apple had moved on from using the Motorola CPUs to using the new PowerPC CPU Macs like the Power Macintosh LC 5200 in 1995, followed by the iconic iMac G3 in 1998.

Pros:-
>> The Macintosh 128K became an iconic all-in-one computer with a built-in monitor and floppy disk drive.
>> The Mac 512K and its enhanced models made good use of its extra RAM
>> Those original 16-bit Mac models were compact and more portable than the IBM PCs


Cons:-
>> The original Mac 128K was ridiculously expensive at $2,495, which had low RAM and only had a built-in monochrome display. Even the early Macs weren’t as affordable as the Apple II models
>> Even though the original Macs were small but their display monitor was so small at near 9 inches
>> The Mac's predecessor, the Apple Lisa had a 1MB RAM whilst the original Mac had 128KB RAM, despite that the Lisa was very expensive than the Mac 128K


Improvements that should have been made:-
>> Well the Mac 128K was pretty much a bad start for having 128KB RAM and should have started with 512KB RAM instead
>> Maybe added more fans, heat sinks and vents as the Mac 128K and 512K models can get hot after some time and intensive tasks
>> And the keyboard and mouse for the Macs seem too small that they should have added the Right-Mouse button, along with the F-Keys and Cursor keys for the Mac.


Sega Mega Drive (Genesis):-
The Sega Mega Drive or Genesis was launched in 1988 to replace the older Sega Master System and to directly compete with the 8-bit Nintendo Entertainment System (NES). The Mega Drive contains more than one processor, as the Motorola 68000 clocked at 7.6 MHz and also the came with a co-processor, such as the Z80 at 3.5 MHz for sound support and backwards compatibility for the Master System ROM cartridges. The graphics quality is fairly good for a 16-bit games console but not quite remarkable. It can display commonly at 320x224 (NTSC) or 320x240 for PAL consoles, plus can display in 320x448 or 320x480 interlaced resolution - but for rare occasions, like for 2 Player split-screen mode in Sonic the Hedgehog 2. And can display 61 colours out of the palate of 512. But the graphics quality isn't powerful enough for simple 3D games that had very few polygons and no detailed textures, as certain Mega Drive 3D games like Steel Talons and M-1 Abrams Tank cannot cope with having the frame rate near over 24 FPS. However, Sega had created a ROM cartridge with a Sega Virtua Processor or SVP for only Virtua Racing game to enhance the frame rates and quality. Plus Sega had also added a CD-ROM technology add-on, known as the Sega CD to boost the quality of using FMV videos and added a faster Motorola 68000 at 12.5 MHz. Which is nearly 75% faster than the Mega Drive's stock M68000 at 7.6 MHz. The FMV video quality was not as good and colourful compared to the LaserDisc video quality and for the upcoming DVD videos.

Pros:-
>> The Mega Drive was slightly cheaper than the NEC PC-FX/TurboGrapx-16 and the SNES, as well as made it more affordable than the Neo Geo consoles, Amigas, Atari STs, as well as PCs.
>> The Mega Drive had an early head-start to compete with the other newer 16-bit consoles and had more game libraries at first than the SNES.
>> The Mega Drive's CPU was near twice as fast compared to the SNES
>> The Sega CD was like an added bonus for improved quality, as the SNES had plans for the SNES-CD project but was never completed
>> The ROM Cartridges are more robust and load faster than floppy disk drives


Cons:-
>> The Mega Drive didn't have enough colours to display as the palette was lower than the Amigas, PCs with VGA support and the SNES. Even the Sega CD video quality didn't look too crisp and clear
>> The Sega 32X add-on wasn't a huge success for the Mega Drive to improve on using 32-bit RISC processors as it was too pointless
>> The ROM cartridges were expensive to buy due to the plastic and pricey circuits used to build those cartridges
>> The SVP was only used for the Virtua Racing game and wasn't as powerful and popular as the SNES Super-FX


Improvements that should have been made:-
>> Sega should have saved their time and investment for Sega Saturn to successfully replace the Mega Drive, instead of wasting it on the 32X project
>> Maybe not launching the Sega Saturn too soon and maybe provide backwards compatibility for the Mega Drive and more
>> The Mega Drive was maybe launched too early as their older Master System was launched 3 years before the Mega Drive first appeared. As Sega could have maybe used a bit more time and improvements for the Mega Drive project to have a slightly higher CPU clock speed and colour palette


SNK Neo Geo (Console):-
The SNK Neo Geo AES (Advanced Entertainment System) console first appeared in 1990, to boast a more powerful graphics quality and faster Motorola 68000 clocked speed of 12 MHz, along with a Z80 co-processor of 4MHz - which is slightly higher than the Sega Mega Drive. The console came in two versions: the Silver version for $399.99 and the Gold version for $649.99. The Neo Geo can display a total of 4096 colours out of the palette of 65,536 colours. Amazing isn't it for a very early 1990s games console, eh? The prices however seem very high for $649.99 to deliver that huge amount of power, which wasn't appealing for poor gamers. The Neo Geo also eventually got a CD-ROM add-on introduced in 1994 and provided the Neo Geo CD console with a more ergonomic gamepad than the original Neo Geo controller. The Neo Geo CD technical specifications were pretty much the same as the original but with more memory and RAM, as well as delivering CD-quality video.

Pros:-
>> The Neo Geo console had superior graphics and speeds than the Mega Drive, CDTV, SNES and the PC-Engine
>> Even though the Neo Geo was expensive, gamers had the option to choose the cheaper Silver version
>> The Neo Geo CD add-on makes it useful for games to have more storage, audio and video quality


Cons:-
>> The Neo Geo wasn't exactly very affordable for poor gamers as the prices were very high compared to the SNES and Mega Drive, even the Game Boy
>> The Neo Geo games library was low as not a lot of games were made due to the high prices for the console as well found it off-putting for game developers to sell their games at a reasonable and affordable price along with the pricey ROM cartridges
>> The Neo Geo controller is bulky and not quite comfortable to use


Improvements that should have been made:-
>> SNK should of at least introduced a low-end model (instead of the Silver version) that is cheaper and more affordable, as the Neo Geo Pocket and Color was released too little too late
>> SNK should of at least made their original Neo Geo console controller more ergo like the Neo Geo CD gamepad


Atari ST:-
The original Atari 520ST, informally known as the “Jackintosh” first appeared in 1985 to compete with the original Macintosh computers and offered a colour display monitor. The main ST computers contain an M68000 clocked at 8MHz with 512KB of RAM for the 520ST models and 1MB RAM for the 1040ST models with an Operating System known as The Operating System or TOS devised by Digital Research who created GEM (Graphics Environment Manager) desktop environment. The Atari ST models were not made with an internal floppy disk drive until the Atari Corporation introduced the STF models in 1986. Tramiel offered the ST machines at a quite low cost at a maximum of $999, which made it more affordable and competitive than its expensive rivals, the Macintosh, the IBM PCs, and the Amigas as their direct rivals. Most ST applications and games were commonly displayed at 320x200 with 16 available colours out of the 512 colour palate, which seems disappointingly low. And their data floppy disks can be formatted and can only store 360KB single-sided 3.5-inch floppy disks or 720KB for double-sided floppies, which is also too low to store data. Eventually, Atari Corporation introduced some upgraded ST models like the Atari STE (E for Enhanced), which increased the colour palate from 512 to 4096, and some other upgrades. However, the STE models had some backwards compatibility issues with some software that wasn't designed for newer STE models, as well as suffered some problems with the TOS v1.06 or later.

Pros:-
>> The launch of the Atari 520ST packages with a colour monitor was priced at a lower $999, which was more affordable than the expensive IBM PCs and Macs
>> The CPU stock clock speed was slightly higher at 8MHz than most other 16-bit computers in the mid-1990s
>> The newer STE and Mega models provided support for Hard Disk Drive to store more data than the floppy disks
>> The Atari ST mouse was slightly more ergonomic than the original Commodore-Amiga mouse
>> The ST designs were quite distinctive and more modern looking than the ageing Atari 8-bit 400, 800 and XL ranges


Cons:-
>> Even though the original ST models supported colour, the available colours and palate were quite low for good graphics.
>> The Atari ST's 32-bit replacement, the Falcon didn't last very long as well as the Atari Jaguar console which had an appalling ergonomic designed gamepad
>> The floppy data disks were prone to get easily corrupted by foreign bodies, and dirt can contaminate the disk
>> The newer STE models suffered some reliability and backwards compatibility issues
>> The STs never had CD-ROM support to try to mitigate the issues with using floppy disks with its slow loading times and how fragile those disks are


Improvements that should have been made:-
>> 16 colours available colours out of the 512 colour palate should maybe at least have more than twice that colour
>> The ST floppy disk data storage should maybe be formated near just below 1MB
>> The ST models would definitely compete better if they had a CD-ROM drive, like the Sega CD, Commodore CDTV & CD32, as well as for the 3DO and more
>> Maybe Tramiel and Gould should have never started their vendettas as well as focused on improving the Quality Assurance and reducing the ST's flaws, instead of having a lawsuit on Amiga Vs Atari ST to mitigate this business feud - besides both the Amigas and STs pretty much didn't succeed well for the future as they both lost to the Windows 3.x and the legendary Windows 95 near the mid-1990s


Amiga 500 (A500):-
The Commodore Amiga range first appeared in 1985 when the A1000 model was the first model created. However, the A1000 did have some teething problems and was slightly more expensive than the Atari ST, as the A1000 was priced at $1,295 The low-end version of the Amiga 500 or A500, on the other hand, was the best selling Amiga model ever priced at $699. The A500 had to overcome some problems with the A1000's buggy operating system and Kickstart ROMs version v1.1 and its high prices, as Commodore planned to have a cost-reduced and smaller model. A500 is powered with a Motorola 68000 clocked slightly higher than 7 MHz, and initially was created and shipped with 512KB of "Chip" RAM, Kickstart Release 1.2 and with some distinctive nicknames for the sound and video chipsets: "Paula", "Denise" and "Agnus" The Original Chip Set or OCS was the first chipset used for earlier Amigas, such as the A1000, A500 and the A2000 using the Kickstart ROM v1.x and using a maximum of 512KB of "Chip" RAM. ECS (Enhanced Chip Set) with a bigger "Agnus" to support between 1MB to 2MB of "Chip" RAM for extra resolutions for 640x200 (NTSC) or 640x256 (PAL) with slightly more colours supported and more gaming features. KickStart 1.3 still supported ECS for over 1MB RAM until the KickStart 2.04 came along for the newer A500+ with a brand new Workbench (desktop interface) with sleeker designs and to support ARexx to replace the lame AmigaBASIC. However later revisions and models of the newer A500+ and the 32-bit powered A1200 models suffered from backwards compatibility as not all Amiga games compiled and built for the original A500 works for the A500+ and the A1200. The A1200 contains a faster 68EC020 CPU but is a low-cost variant to the 68020, to make the A1200 more affordable compared to the expensive A4000 with a slightly newer 68EC030 or 68040 CPU. The A1200 contains an AGA (Advanced Graphics Architecture) chipset that supports more colour, by displaying a max of 256 colours out of the astonishing 24-bit Colour palate of 16 million colours. Whilst the older A500 generally displayed 32 colours out of 4096. And unlike the Atari ST, Commodore introduced CD-ROM supported models like the CDTV computer in 1991 and the CD32 console in 1993.

Pros:-
>> The launch of the Amiga 500 was priced at $699, which was $300 cheaper than the Atari STs and became quite a good success for the European markets
>> The CD-ROM support for the CDTV and CD32 was useful for better sound and audio quality and to mitigate the issues with using floppy disks with their slow loading times and how fragile those disks are
>> Many Amiga games for the ECS chipsets had the advantage of additional gameplay features using extra RAM and having more colour support than the Sega Mega Drive
>> The A520 RF Modulator port for the TV signal I/O was useful and for later A500 models to toggle PAL/NTSC modes as well as split the L/R sound signals into the Red and White RCA sound ports
>> The newer A500+ and the A600 made some good uses for the newer KickStart 2.0x revision for enhanced Workbench features and additional options


Cons:-
>> The CPU stock clock speed was slightly lower than the Atari ST and the Sega Mega Drive, as the 68000 wasn't powerful enough to cope with too many sprites and for simple 3D games to have decent a frame rate like Frontier, Aquaventura, F/A-18 Interceptor, and MicroProse F1 Grand Prix
>> The A500+ and A600 weren't fully compatible with some of the older software, which was required to be patched by Cracktros and WHDLoads who had those 680x0 fixes and for AGA.
>> The floppy data disks were prone to get easily corrupted by foreign bodies, as well as not as robust and loaded faster than the Sega Mega Drive and SNES ROM cartridges
>> Even though the Amiga supported the Atari Joysticks, many gamers argue that using only 1 fire button wasn't enough as some (but not all) games supported a 2nd or alternate fire button


Improvements that should have been made:-
>> 32 colours available colours out of the 4096 colour palate was maybe too low as most games should at least use 64 or more colours as early Amiga games suffered from the lack of available colours until the AGA chipset arrived
>> Commodore had financial troubles and should maybe not have wasted their time and efforts on the A500+, and A600 projects as those models didn't last long and suffered from their backward compatibility issues
>> The A500 should of at least had 1MB of "Chip" RAM to start off with like the Atari 1040ST did back in 1985, as the A500 was released 2 years after the ST came, to use that extra RAM to their advantage instead of 512KB of RAM
>> Maybe Tramiel and Gould should have never started their vendettas - as mentioned for the Atari ST
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