{Send follow ups to comp.sys.mac.advocacy. Sorry about the header but the 
Pnews here does not let one easily change the headers and I gave up after a 
year of trying. This sheet is also available by FTP on sumex-aim.stanford.edu 
(36.44.0.6) in the info-mac/report as mac-ibm-compare177.txt.}
Mac & IBM Info-Version 1.7.7

The reason for this general data sheet is to consolidate and condense the 
information out there, so that people in both camps can be clear and accurate 
about what they are saying about their machines.  Since computer technology 
is always changing there are always going to be points in which the sheet will 
be lacking or incorrect on information.  So, please just don't say the sheet 
is incomplete or incorrect but also give me clear and concise information to 
make the needed corrections.  All prices are in US dollars.
To keep this data sheet organized please provide, if possible, article 
citations for the information provided or corrected and keep the opinions to 
a minimum.  As this is a general data sheet, keep the info provided simple so 
I can understand what is being talked about and can explain it to others. 
Finally, keep the information relevant to the section corrected {For example, 
OS code in ROM is software contained in hardware, so no more of the 'but it 
is supported in OS disk software' data for the hardware section, please}. 
Thank you.
Note:  for proper reading off line this document should be in 9 point Monaco.

Special thanks to ANDREW@aardvark.ucs.uoknor.edu (Chihuahua Charlie), 
andrew@frip.wv.tek.com (Andrew Klossner), bell-peter@YALE.EDU (Peter Bell), 
bcoleman@hayes.com (Bill Coleman), cj00+@andrew.cmu.edu (Carl B Jabido), d88-
jwa@nada.kth.se (Jon Wtte) ephraim@Think.COM (Ephraim Vishniac), 
fj05+@andrew.cmu.edu (Faisal Nameer Jawdat), gsidler@cafe.eecs.nwu.edu 
(Gabriel Sidler), julian@deepthnk.kiwi.gen.nz (Julian Harris), 
Erick.Krueger@um.cc.umich.edu, krueger@engin.umich.edu, 
matt@wardsgi.med.yale.edu (Matt Healy), mark@bilpin.co.uk (Mark Allerton), 
jokim@jarthur.claremont.edu (John H. Kim), mem@jhufos.pha.jhu.edu (Mel 
Martinez), nan@matt.ksu.ksu.edu (Nan Zou), pwagner%us.oracle.com, 
s_fuller@iastate.edu, strobl@gmd.de (Wolfgang Strobl), 
jkirvin@pafosu1.hq.af.mil, phill@ichips.intel.com, 
shaikha@duvm.ocs.drexel.edu, sxjcb@orca.alaska.edu (Jay C. Beavers), Lewis 
Kawecki@novell.com, lamont@catfish16.rtsg.mot.com (Bradley Lamont), 
cerro@mbcl.rutgers.edu ("Cerro, Joseph A"), mpark@utmem1.utmem.edu (Mel Park), 
logullo@applelink.apple.com (Jeff Logullo), zrai02@hou.amoco.com (Robert 
Irlbeck), and mikew@apple.com for providing some of the information that made 
this list possible.
 Contents
CPUs
Hardware
 Monitor support
 Expansion
Operating system
 OS Number Crunching
Networking & Printing

The CPUs
 Note: I am only showing Motorola & Intel CPUs used in Mac and most IBM/PC 
clone machines. For example, since Apple never used the Motorola 68008 and 
68010 in the Mac these chips are not listed. Years only appear with dead CPUs 
and indicate first to last year used as a CPU.
Cache note:  both IBM and Mac use caches external to the CPUs. These external 
caches increase the speed of the CPU but are not a part of it.  In most of 
the present Macs there are external caches built-in while with IBM they are 
optional {Though machines are generally sold with them installed}.  Since 
there are many different external caches {CPU-Mac and IBM; SCSI, video, disk 
and static RAM-Mac}, each having a different effect on CPU performance, and 
they are machine {32KB static RAM cache in IIci, IIfx, and IIvx}, seller 
{cache card installed in some IIcis} or expansion {IIci cache cards go up to 
128KB} dependent, I have decided to leave them out of the list.
Note:  ALU is industry's de-facto standard for CPU bit classification.
IBM     ALU  Registers    External     CPU     Features/
CPU                     bus  address  cache    Notes
8088(6) 16      16    8 (16)   20     none     {1981-9} {198?-9}
80186   16      16      16     20     none     {198?-9?} segmenting
80286   16      16      16     24     none     80186 + Protected Mode
80386   32      32      32     32     none     MMU & 32-bit Protected Mode 
486sx   32      32      32     32    one 8K    80486 - FPU
80486   32      32      32     32    one 8K    80386 & FPU
486dx2  32      32      32     32    one 8K    doubled internal clock rate*
486dx3  being demoed. 20/60 MHz, 25/75 MHz, and 33/99 MHz planned.
Pentium 32      32      64     32    16K code, CISC chip with RISC-like  
   5                                 16K data  features, 2-issue superscalar, 
 [P 5]                                         386 Write-Back, 64-bit
                                               FPU path, pipelining; Speed:
                                               SPECint92: 64.5; SPECfp92:
                                               56.9**

386sx: 386 chip with 32-bit internal/16-bit external architecture.
286 and 386sx chips can address to 16MB maximum RAM.
386sl: low power(3.3V) 386sx with built-in power management.  Used mainly on 
laptops.
386slc: IBM 5V 386sx with a 16k on-chip cache added (John H. Kim).  As far as 
John H. Kim knows it is only used on IBM models.
486slc: Neither of two chips that have this name have a FPU.  Cyrix: basically 
486sx in 386sx socket with 1k cache and improved integer math speed.  IBM: 
equivalent to the 486sx except it has a 16k on-chip cache.

* ex. for 486dx2/50, chip runs 50 MHz rest of machine runs at 25 MHz.
***(PC Week 04/12/93; PC Mag 4/27/93:138) "The latest in a line of CISC chips" 
(PC Mag 4/27/93:110)  Samples released March 22, 1993, but machines will not 
be announced until at least May 1993 (PC Week 2/08/93).  $1000 a CPU; systems 
$5000 and up (PC Mag 4/27/93:110). 

Mac     ALU  Registers    External     CPU     Features/
CPU                     bus  address  cache*   Notes
68000   16      32      16     24      none    {1984-1993} 16MB limit**
68020   32      32      32     32    256 code  {1987-1992} parallel processing
68030   32      32      32     32    two 256   68020 + MMU, 16K burst mode
68LC040 32      32      32     32     two 4K   68040 - FPU
68040   32      32      32     32     two 4K   MMU, FPU, pipelining, doubled 
                                               internal clock rate***
68050	development discontinued in favor of 68060
68060   32      32      32     32     Branch   68040 + a better FPU,  
                                      target   superscaler pipelining, cache 
                                               line bursts, equivalent 
                                               capabilities & speeds to 
                                               Pentium*#

*includes data and instruction {code} caches.  The 68030, 68LC040, & 68040 
have built-in caches for both.
**68000 Mac designs created a 4MB limit.
***The 040 has 2 clocks, an internal processor clock [PCLK] that is 2x freq of 
external bus clock [BCLK] which is the one used to rate the chips 
(Bradley Lamont; Motorola 68040 data book).  Some compilers produce programs 
sensitive to the PCLK and so they act as if the 68040 was a clock doubler 
chip, but this very compiler and program dependent.  Compliers maybe written 
to allow programs to take consitant advantage of the 68040's PCLK in the 
future.  As it is now, studies such as one in a Byte article {which showed 
040/25 ~486/50 and roughly ~486dx2/50} are very dependent on the machine, OS, 
and programs tested and as such are not representative of general performance.
*#Motorola claims (PC Week 09/07/92; 09/14/92).

As the PowerPCs are to be in both IBM and Mac machines I have listed them 
separately to eliminate redundancy.  They are Motorola CPU RISC chips.

PowerPC ALU  Registers    External     CPU     Features/
CPU                     bus  address  cache    Notes
MC98601 32      32    32 int   64     32K      Speed:  SPECint92: 50; 
 [601]                32 fp         combined   SPECfp92: 80*
                                      I/D      
MC98603: low power MC98601 for desktop & portable systems. Out by end of 1993.
 [603]
MC98604: high performance MC98601 for high end machines. Out by 1st Q 1994.
 [604]
MC98620 64      64    32 int   64     32K      Out by mid 1994.
 [620]                32 fp         combined    
                                      I/D      

*(PC Week 04/12/93; PC Mag 4/27/93:138).  Select venders were sent sample 
MC98601 chips by Motorola 2/93 (PC Week 2/08/93), and some NuBus boards 
containing early samples of PowerPC 601 have been given to Apple's "A-list" 
developers (PC Week 12/7/92; MacWeek 12/14/92).  MC98601/50MHz-$280;
MC98601/66MHz-$374 (PC Week 4/12/93).  Systems: ~$3500 with ~$2000 versions
out by mid 1994 (PC Week 4/12/93).

CPUs Comparison List
As a general rule of thumb Motorola chips are faster than Intel chips at the 
same frequency {030/25 ~= 386/33; 040/25 ~= 486dx/50}, but Intel has chips at 
higher frequencies than Motorola, so this evens out.  The Macintosh Bible 4th 
ed. supports the comparisons between Intel and Motorola chips for the 68020 
and above.

<=80186    ~ 68000 {16-bit vs 16/24/32-bit chip [data path/address 
lines/data & address registers].  The 4MB limit on the 68000 Macs brings it 
down to the 80186 and lower chips, otherwise it would compare to the 80286.}

286        ~ 68020 {hardware segmenting vs. 68020's 32-bit ALU and these chips 
come have no usable built-in MMU unlike their successors [80386, 68030].  The 
hardware segmenting's protected mode is used by OS/2 1.0 => and Windows 3.X. 
The use of the hardware segmenting and their 16-bit nature put the 286 between 
the 60000 and 68030 in features and the LC's 16-bit data path strenghthens the 
286 ~ 68020 comparison.}

386       ~ 68030 {Two 32-bit chips with MMUs, and protected memory.  A/UX 3.0 
is at present the only Mac OS to use the 68030's protected memory feature for 
apps.  System 7.x uses this feature to protect a RAM disk created by the 
Memory control panel but this is supported only on Powerbooks and Quadras.  
The Color Classic and LCII 16-bit hardware data paths makes the 68030s in them 
comparative to 386sxs.}

486sx   ~ 68LC040 {same as 486 and 68040 without the FPU; used as a low cost 
solution for people who do not need the FPU.  Only with programs sensitive to  
PCLK & pipelining does the 68LC040 behave like 486dx2 - FPU or a '486dx2sx'.}

486     ~ 68040 {two 32-bit microprocessors with built-in FPU, MMU, 8K 
internal cache (which is implemented as two 4K caches in the 68040 and one in 
the 486).  Only with programs sensitive to PCLK & pipelining does the 68040 
behave like a 486dx2.}

Pentium   ~ 68060 {Both are planned to be superscalar but both have heat 
problems.  These chips may flounder against the cheaper (PC Week 3/08/93; 
4/12/93; PC Mag 4/27/93:110), earlier released (PC Week 12/7/92; MacWeek 
12/14/92; PC Week 2/08/93), less leat producing {160 degrees F for Pentium
(PC Mag 4/27/93:118)}, and partly ported to PowerPC chips.} 

PowerPC   = PowerPC {This CPU line is planned to run programs from DOS, 
Windows 3.x, OS/2 and Mac OS on top of PowerOpen-A/UX 4.0 [UNIX] and later 
Pink [Taligent OS] by using emulators or, if necessary, the OSes themselves in 
a 'shell' a.k. how SoftPC or OS/2 does DOS.}

Hardware 
{In an effort to remove the 'reconfiguring the system almost every time you 
add something' requirement for add-in cards, drivers, video, and operating 
systems in the IBM world, Intel, Microsoft and 12 other hardware and software 
developers are working out 'plug and play' standards (PC Week 03/08/93).}
Color Support/Display
 Mac: 30.24 MHz Pixel Clock standard.  All present Macs support the use of 
32-bit color through 32-bit color QuickDraw in ROM.  32-bit color QuickDraw 
allows an almost transparent capability to display and edit X-bit images in Y-
bit color and retain ALL the colors of Y-bit color [Where X and Y 
independently are 1, 2, 4, 8, 16, or 32] regardless of monitor resolution {63 
dpi [12" color] to 94 dpi [PaletteBook]} or monitor type {including 
autosynchronous VGA, MCGA and SVGA monitors with ranges including 66.7 hz 
vertically and 35 kHz horizontally and only a hardware video adaptor (MacUser 
Aug 1992: 158-176).  Older machines that supported color {SE/30, II, IIX, and 
IIcx} had only 8-bit color in ROM and needed a software patch to use 32-bit 
color (MacUser Special 1993:28-29).  
To keep costs down and speed up most Macs have only 8 or 16 bit display 
capability built-in, but most of those can be expanded to display 24-bit 
color.    Presently QuickDraw is optimized for 72 dpi display; QuickDraw QX 
will change this.
In addition, QuickDraw allows, in Macs with a NuBus slot, more then one 
monitor to be used in any combination, from two monitors showing the same 
thing to multiple monitors acting as one large large monitor with any degree 
of overlap of the pictures.
VRAM: Video RAM.  Standard for present non-PowerBook Mac's handling of 
 built-in video {from a 32-bit color palette}. VRAM provided runs a 8-bit
 color 640x480 display; expandable to 16-bit color or a 8-bit 832x624 display. 
Sound output:  Standard in all Macs since the 128K.  Stereo sound became 
 standard with the SE/30.

IBM:  Even though PCs have ROM BIOS definitions of how the operating system 
interacts with the video hardware (Nan Zou), the use of drivers bypassing 
BIOS, video hareware inconsitancies {see Super VGA below} and nonstanderzation
of clone BIOS have left resolution of video display hardware, OS and program 
interaction up to the OS and video hardware in question (Faisal Nameer 
Jawdat). In addition, IBM and clone makers never bothered to provide a 
standard hardware mechanism for software to determine what display mode is 
actually present (Matt Healy) nor a standardized screen-drawing toolbox {like 
Mac's QD}. As a result the OS must be very well written to detect some modes, 
especially with some third party cards or to use them consitantly {At present 
things are so dependent on the interaction of the program, OS, print driver 
and monitor card that editing 32-bit pictures regardless of color mode, OS, 
and monitor type/card combination as one can do on the Mac is impossible with 
an IBM.  For example, one cannot edit a 32-bit color picture done on a OS/2 
486 with a SVGA monitor on a 386 with VGA {18-bit color palette} and DOS 5.0 
and still have ALL the colors one started out with}.
Later IBM machines will have integrated graphics accelerators, faster 
processors, and modular upgradeability and may have built-in sound cards, CD 
ROM, and Ethernet (PC Week 12/14/92).  
MDA: Monocrome Display Adapter
 original character-mapped video mode, no graphics, 80x25 text.
CGA: Color Graphics Array
 320x200 4 colors or 640x200 b/w, 16 color palette, bad for the eyes.
EGA:  Enhanced Graphics Array
 640x350 16 colors from 64 color palette [and some lower res]; some versions 
 could run at 256 colors, bearable on the eyes.
VGA:  Video Graphics Array*
 320x200 at 256 colors, 640x480 at 16 colors, and some others, these two are 
 the most commonly used.  All modes have a 256K CLUT, from a 
 18 to 24-bit {IBM} or a 32-bit {Mac} color palette.  25.175 MHz Pixel Clock
 (Mel Martinez).  Monitors use analog input, incompatible with TTL signals
 from EGA/CGA etc. 
MCGA:  Multi-Color Graphics Array*
 subset of VGA that provides all the features of MDA & CGA, but lacks some EGA 
 and VGA modes, like VGA 640x480x16 (Dictionary of Computer Terms-DCT).  
 Common on the initial PS/1 implementation from IBM and some PS/2 Models.
SVGA:  Super VGA*
 This is not a standard in the way the others were, but instead was a 'catch 
 all' category for a group of video cards.  As such, with each manufacturer 
 using their own implementation scheme, SVGA was chaos with people debating
 as to what is SVGA and what is not.  In an effort to make SVGA more of a 
 standard VESA was established and is used in the newer units, but things
 are still a mess.  Video is either 512K [~1990] or 1M [today], resolution
 of 800x600 and 1024x768 at 16 and 256 colors are common, newer ones [since 
 1990] have the Sierra HiColor RAMDAC, giving 15-bit 32,768 colors at 800x600, 
 some of the very newer ones [~6/92] can do 24 bits per pixel [usually 
 at 640x480].  Speedwise, too much variation, some very slow [Western Digital 
 Paradise based, for example], some very fast [S3 86C911 based, for example], 
 some are so-so [like Tseng ET4000, a very popular chipset].  Some limiting 
 factors overcome by 40MHz VL Bus & 386's linear address mapping were: 
 8.33 MHz ISA bus, AT architecture where the CPU looks at the card through a 
 64K "window", etc.
Other non-SVGA standards: 
8514/a:
 IBM's own standard, interlacing graphics accelerator with graphics functions 
 like linedraw, polygon fill, etc. in hardware. Some clone implementations 
 from ATI are the fastest video available today, though some clone models do 
 not have interlacing. 
TMS34010/34020: high end graphics co-processors, usually >$1000, some
 do 24-bit, speeds up vector-oriented graphics like CAD.
XGA:  eXtended Graphics Array
 newer and faster than 8514/a, only available for MCA bus-based PS/2s, clones 
 are coming out soon.  Emulates VGA, EGA, and CGA (DCT).  Max resolution at 
 1024x768x8b, same as 8514/a, also some 16 bpp modes.
XGA-2
 Accelerates graphics functions up to 20 times faster than standard VGA in
 Windows and OS/2, including line draws, bit and pixel-block transfers, area
 fills, masking and X/Y addressing. Has an intelligent way to detect and co-
 exist with other XGA-2 cards, so multiple desktops like on the Mac may not be 
 far away.  Since this is an architecture, its resolution and color depth 
 isn't fixed {IBM implements only 16-bit [65,536] color, while other 
 companies can have 24-bit color through IBM technical licenses}. Refresh 
 rates up to 75 Hz, ensures flicker free, rock solid images to reduce visual 
 discomfort, and is VGA compatible. Up to 1280x1024 on OS/2.
*some monitor types usable by Mac-See Mac section above for specific details.

Expansion
Both Mac & IBM
SCSI: only external device expansion interface common to both Mac and IBM.
 Allows the use of any device: hard drive, printer, scanner, Nubus card 
 expansion {Mac Plus only}, some monitors, and CD-ROM.  
 Main problem:  there are a lot of external devices which are internal 
 terminated which causes problems for more then two devises off the SCSI port 
 {A SCSI chain is supposed to be terminated ONLY at the begining and at the 
 end.  Any other set up causes problems for either Mac or IBM}. 
SCSI-1:  7 devices per SCSI controller.  8-bit asynchronous {~1.5MB/s ave}
 and synchronous {5MB/s max} transfers.  Difference is due to SCSI-1 software
 drivers.  "Fast SCSI-1" is a misname for 8-bit SCSI-2 in SCSI-1 mode
 {see SCSI-2 for details}.
SCSI-2: 10 devices per SCSI controller in SCSI-2 mode.  SCSI-2 is fully
 SCSI-1 compliant and 8-bit SCSI-2 tends to be implemented as a very fast
 SCSI-1 since it does not require the different controller interfaces in  
 hardware and software that 16 and 32-bit SCSI-2 do.  Transfer speeds are
 4-6MB/s with 10MB/s burst {8-bit}, 8-12MB/s with 20MB/s burst {16-bit}, and
 15-20MB/s with 40MB/s burst {32-bit/wide and fast}.  Since 8-bit SCSI-2 can
 use SCSI-1 software drivers and hardware at 8-bit SCSI-2 speeds and as such
 is limited to 7 devices sometimes it is mistakenly called "fast SCSI-1". 
 16-bit fast SCSI-2 requires a SCSI-2 software driver and SCSI-2 electronics
 but can still use the SCSI-1 ports.  Wide 16-bit and 32-bit SCSI-2 require a
 different SCSI port, electronics, and software driver from SCSI-1 {Which
 makes them more expensive than other SCSI interfaces}.
Mac SCSI: asynchronous SCSI-1 built-in standard since the Plus.  Even though 
 Apple developed some specifications for SCSI controlers, the OS SCSI Manager
 needs to be rewritten to take full advantage of the features of both SCSI
 interfaces.  As a result present SCSI-2 Macs use 8-bit SCSI-2 as a fast 
 asynchronous SCSI-1.  Presently Quadras are the only Macs with a SCSI-2
 controller chip built-in (Digital Review, Oct 21, 1991 v8 n33 p8(1)) 
 though they lack some other parts of the hardware, like the wide SCSI-2 port 
 interface.  Since other Macs require a NuBus card to use SCSI-2, older NuBus 
 Macs had a bottleneck due to the speed of the NuBus and CPU.  Rumor-some
 Cyclone Macs {June} will come with a wide & fast SCSI-2 port standard 
 and have a rewritten OS SCSI manager.
IBM SCSI:  SCSI-1 is not too wide spread yet, generally not bundled with 
 systems, except as add-on {EISA and VESA Local Bus adapters avalable}.
 Like the Mac, 8-bit SCSI-2 is used as a very fast SCSI-1 by most controllers
 out there.  Unlike the Mac, IBM has no exact SCSI controller specifications
 which results in added incompatibilities for SCSI.

Mac
Memory expansion: with a few exceptions the Mac has used non-parity 30-pin 
 8-bit SIMM memory expansion since the Plus.  While 32-pin 9-bit parity SIMMs
 could be used in these Macs, only special IIcis could make use of the parity 
 feature {By convension both SIMM types are called 32-pin SIMMs}.  The IIfx 
 used 64-pin parity SIMMs.  The LC III, C610/650 and Q800 all use a new 
 72-pin SIMM that is accessable by 32-bits at a time and is used in IBMs.
 The Mac does a complete memory check at startup by writing/reading every
 memory location; if something is seriously wrong with a SIMM the Mac will
 not boot and give a sound chord indicating what the problem is.
 Since Macs made before Feb 15, 1993 managed memory baced on data path, SIMMs 
 had to be installed in pairs {16-bit} or in sets of 4 {32-bit}.  The Centris 
 650 and Quadra 800 eliminate this with a new memory management setup that 
 allows memory to be upgraded one SIMM at a time.  If the SIMMs are the same 
 size are used then the memory is 'interleaved' across the two SIMMs resulting 
 in a 10-15% performance boost on RAM access (MacWorld Apr 93: 108-109).
Printers, ADBs, and modems: built-in interfaces standard.
Monitor interface and sound input: built-in on most present macs. 
PDS: Available in SE & all present non-Powerbook Macs. 16-bit {SE, 
 Portable, LC, LC II, Classic line} and 32-bit.  Operates at CPU's MHz.  
 Maximum through put: data path in bytes*CPU's MHz {Q700/900 & C650: 
 4 * 25Mhz = 100MB/s; Q800 & Q950: 4 * 33Mhz = 132MB/s}. Standardized with
 the LC and 040 bus designs.  With an adapter one NuBus card can be used in 
 IIsi and C610.  Problem: some cards have timing dependency which slows 
 through put down.
NuBus Mac II: 32-bit, 10 MHz bus clock, 1-to-1 transaction/bus cycle ratio,
 and contiguous, hand-shake transactions at ~10-20MB/s; theoretical peak:
 40MB/s.  Built-in on all Modular Macs except the LC series, C610, and 
 Performa 400.  The SE/30 could be adapted to use this and there was even a 
 Mac Plus SCSI NuBus.  Supports every possible expansion from CPU to Ethernet 
 to DMA.
NuBus 90: NuBus Mac II back compatable. 20MHz bus clock, avg throughput:
 ~30MB/s; burst mode: 80MB/s.  Future card designs will be 7" instead of the 
 old 12".
QuickRing:  A peer-to-peer bus used in parallel with NuBus 90.  Apple's 
 VLBus - "Architecture is identical to that of VLBus" (Byte 10/92:128).
 Burst mode: 350MB/s (Byte 10/92:128). In development.
CPU expansion: handled either through the PDS or the NuBus.  Unlike PDS,  
 Nubus CPU cards {example-Radius Rocket} allow use of multiple processors at 
 the same time.  This is like having two or more Macs in the same box able to 
 dual task or joinly process depending on the card or software involved {Each 
 NuBus card needs its own memory but most NuBus cards of this type come with 
 8MB RAM SIMMs on the card standard}.

IBM
Memory expansion:  parity SIMMs, non-parity SIMMs {some newer models do a Mac-
like SIMM memory check}, or a dozen or so different types of memory boards.

HD Interfaces {limited to hard drives by design or lack of development}: 
MFM:  Modified Frequency Modulation, RLL:  Run Length Limited
 only used with smaller [² 60mb] hard drives.
IDE:  Integrated Device Electronics 
 Asynchronous {~5MB/s max} and synchronous {8.3MB/s max} transfer.
 currently the most common standard, and is mainly used for medium sized 
 drives. Can have more than one hard drive. 
ESDI:  Enhanced Small Device Interface
 ~1.25MB/s throughput. generally considered better interface than SCSI-1 in
 many ways but not common enough for practical consideration.  Outside of
 hard drives, device choices are very limited compared to SCSI-1. 

BUS interfaces
{New 'plug and play' ISA and EISA compatable cards may have problems working 
with old cards (InfoWorld; PC Week 03/08/93; Vaporware 4/93).}
ISA
 8 & 16-bit interfaces common. Has 24-bit data path limit {which produces a
 16MB limit for which there are software workarounds} (PC Mag 4/27/93:105).
 1.5 MB/s (Byte 3/93:132).  Uses edge-triggered interrupts, can't share them,
 hence comes the IRQ conflict.  Limited busmastering capabilities, some cards
 aren't bandwidth limited {COM  ports, LPT ports, game ports, MIDI card, etc.}
 while others are {video and disk controllers}.  Dominant factor, but it's
 showing its age.  Most ISA motherboard designs are 16-bit
 (PC World Feb 1993: 144-5)}.  
MCA {Micro Channel}
 IBM's 16 and 32-bit bus; "allows use of more than one CPU in a computer" 
 (DCT) and anything can talk to anything, as fast as the two components 
 involved can handle it. Never took off because it was incompatible with ISA 
 and EISA.  Planned to be bus interface of IBM PowerPC 601 (Carl Jabido).
EISA {NuBus Mac II is closest Mac equivalent}
 32-bit, 8.33 MHz, burst mode: 33MB/s.  It also has the ability to 
 self-configure cards like MCA and allows multiple bus masters, sharable 
 interrupt and DMA channels and multiple CPU use.
VESA Local Bus: VLB {Sometimes mistakenly refereed to as PDS}
 Local Bus standard. Runs at CPU clock rate,  Burst modes: ~130 MB/s{32-bit}
 250 MB/s{64-bit} (Byte 10/92:128).  Limited to three slots but allows bus 
 mastering and will coexist with either ISA or EISA. Consitered ideal for 
 video and disk I/O.  DELL has filled a claim that this violates one of
 their patents (Mel Martinez).
QuickRing: Apple's faster {350 MB/s burst} version of VLB architecture
 (Byte 10/92:132).  Might show up in some IBM and PowerPC machines
 (Byte 10/92:132-133). In development.
PCI
 Intel's version of Local Bus that is intended to totally replace 
 ISA/EISA/MCA.  In development.

OSes {assumes full installation [print drivers, fonts, Multifinder, etc.]
and multiple application use.}
Mac
512K to 1MB of OS and hardware commands have been put into ROM.  This allows 
Apple to control its machine by putting key hooks for the Mac OS {QuickDraw, 
menu commands, print, mouse, SCSI & sound drivers, etc} in ROM, which require 
clone makers to use the ROM chip or read ROM on to disks {Which requires 
access to the proper Mac since different Macs have slightly different ROM 
chips; Plus vs Classic for example.}  With key hooks for the OS support 
interface in ROM, programers do not have to worry as much whether the disk OS 
has the necessary hardware commands or that those commands are consitant and 
therefore can write smaller programs.  This also allows Apple greater control 
over hardware-software standards and that the disk OS can be smaller and, with 
some of the tookbox command code in ROM, with lower RAM requirements then a 
totally disk based OS.  Macs use Masked ROM which is as fast as DRAM (Jon 
Wtte).
6.0.7: Single program usage base requirements: 1 MB and DD floppy, 
 cooperatively-multitasking base requirements: 2MB and HD floppy.  
 Features a GUI, cooperative-multitasker [MultiFinder], standard program 
 interface, & standard stereo sound support [snd]. Network receiving part of 
 AppleShare software is bundled with the OS. Has a 8MB RAM barrier and is a 
 24-bit OS. Some third party products allow 14MB of Virtual Memory as long as 
 real RAM is below 8MB.
6.0.8: 6.0.7 with 7.0.0 print drivers.
6.0.8L:  System 6 for some Macs that require System 7.0.X.
7.0.X: Base requirements: 2MB, 40MB Hard Drive, and 68000; De-facto standard 
 to run all features well: 4MB, 80MB Hard Drive, and 68030 {lowest present 
 non-portable Mac configuration}.  Using up to 10.08MB {This is EVERYTHING on
 system disks} of hard disk space this has 6.0.7 features plus program linking 
 within and between computers [IAC], built-in server capabilities {Filesharing 
 can be used by older OSes using AppleShare Client software and can be 
 accessed by 10 macs max; 4-5 is more speed practical, IAC requires 7.X}, 
 Virtual Memory in machines with MMU{1.6 times real RAM for least noticeable 
 IIsi speed degradation}, drag and drop, QuickTime & built-in TrueType 
 support.  Supports sound input [AIFF and snd formats] for most present 
 machines.  Can access up to 1GB of true RAM and 4GB of virtual memory and is 
 both a 24 and 32-bit OS.  To use real RAM beyond 8MB it must be in 32-bit 
 mode and on older machines requires the 'Mode 32' extension.  Apple's last 
 'free' OS.
7.1.0: 7.0.1 with WorldScript support, speedier, and less RAM usage than 
 7.0.dot (MacWeek 8/24/92; 9/14/92; PC Week 9/7/92). To run in 32-bit mode 
 on older machines it requires the 'Mode 32' or '32-Bit Enabler' extension. 
 Marks the start of Apple saling its Mac OS instead of allowing free upgrades
 {Bundled with new machines, $49 for 7.0.X upgrades, $99 otherwise}.
 [The installer has a bug that when upgrading it may keep some old system 
 fonts from the previous system inside the system file.  This can eat up any 
 RAM benefits and cause other problems.  Apple itself recommends removing all 
 fonts from the system file.]
A/UX 3.0 [UNIX]: Needs 8MB RAM {12-20MB suggested}, 160MB hard drive, and 
 a 68030 or 68040 equivalent to run.  This 32-bit preemptive multitasking OS 
 is large due to being UNIX and needing translators between it and the Mac 
 ROMs.  Price: $709.
Note: sound output was supported in OSes 3.2 to 6.0.5 by many formats 
including the following:  snd, WAVE, ASND, FSSD, QSSN, SMSD, SOUN, dc2d, and 
DCFL.  In 6.0.7 the sound manager was optimized for the sound standards 'snd' 
and AIFF which causes some playback problems for the old formats, though most 
still play.

IBM
 Machiness have little GUI code, data, and hooks present in hardware for 
programmers to work with, so most of the coding must be provided in the OS.  
Since hard disks were slow the disk OS code is read into RAM.  In addition, 
what little ROM code there is also read into RAM {a process called Shadow ROM}  
This results in faster implementation since RAM is faster then PROMS or 
EPROMS.  Having most of the OS code on disk has the advantage of being able to 
better optimize the code given a certain piece or collection of hardware which 
is harder with a ROM based system due to the 'patches' needed.  In addition it 
reduces the need for and size of patches if a major revision of the hardware 
support is needed.
Side note:  The FTC charged that MicroSoft formed a OS trust by not providing 
all feature documentation for its OSes to developers outside MS and designing 
its Windows and DOS apps to fail under OS/2 ("Undocumented Windows") and 
"There is deliberate code in [Windows] NT Beta which causes the install to 
abort if OS/2 Boot Manager is present" (Gregory Hicks, Info-IBMPC Digest V92 
#201).  Due to a conflict of intrest by one member the vote of the FTC 
judicial council for action against Microsoft was a tie which resulted in no 
action.  Rumors-the FTC will presue the matter, likely to the point of 
choosing a new member or whole new council.  In addition the government has 
turned down Microsoft's copyright of "Windows" which would allow it to charge 
a fee for developers using their hooks (PC Week 03/08/93).
MicroSoft OSes
DOS 5.0: Has a 640K barrier with its own memory manager, a 1 MB barrier 
 with third party memory managers.  This 16-bit OS requires that each program 
 must provide its own print drivers and be 16-bit {Programs need to be DOS 
 Protected Mode Interface (DPMI) compliant and running on a 386dx [32-bit 
 Protected Mode] to break these barriers}.  Contains the GUI shell present in
 DOS 4.0.
DOS 6.0: DOS 5.0 with the added features of a built-in file compresion, disk 
 defragmenter, debugger for the CONFIG.SYS file. It needs a $80 module for 
 networking {Cost: $50 through 5/93, after that $129.99} 
 (Byte April 1993:44-46).
DOS 7.0: 32-bit DOS. In development (PC Week 04/05/93).
Window 3.0: Runs on top of DOS.  Breaks 640K and 1M barriers but still has to 
 deal with DOS file structure.  Base requirements: 1MB, floppy and 286; to
 run well 2MB, hard drive, 386sx and fast display adapter {> 8-bit}.  Has the
 equivalent of Mac's QD called Windows GDI [Graphics Device Interface].
 This does not have a consistent application interface {Like early Mac
 programs  (1984-1985)} nor a very large program base {compared to DOS} and
 still tends to slow the machine down (Info-IBMPC Digest V92 #186) with speed
 is more dependent on the display adapter then on the CPU (Bill Coleman).
 Window programs tend to be disk and memory hogs compared to their DOS
 counterparts (Byte April 1993:98-108).
Window 3.1: A faster version of Window 3.0 with better memory managment. Base 
 requirements 1 MB, hard drive and a 286 ;to run well 2MB, hard drive, 386sx. 
 Apple plans to release its print drivers for this (PC Week 12/28/92).
Windows for Workgroups:  To run well: 4MB RAM and 386dx (PC World Feb/93:160).  
 Intermediary between Win 3.1 and Windows NT.  It is basically Windows 3.1 
 with built-in peer to peer networking support.
Windows NT:  Beta release takes about 50MB of disk space [including the 
 swap file], and 12MB RAM {Betas are notorious for RAM usage especially in 
 the interaction between debuging code and program compliers, hence the 
 reports of 24MB requirements}.  Released version supposed to need 8MB RAM 
 but, Gates himself now recommends 16MB RAM (PC Week 04/15/92).
 This 32-bit OS has Protected mode multitasking, multithreading, symmetric 
 multiprocessing, a recoverable file system, and 32-bit GDI.  Has built in
 networking that is OSF DCE compliant and can handle up to 4GB of RAM.  Even
 though some people see a July 4 release date (InfoWorld Nov 16/92), rumor
 is that the final version will not be available before Oct 1993
 (InfoWorld May 25/92; July 6/92; Vaporware 07/92; 08/92) or 4th quarter 1993
 (PC Week 09/28/92). Windows upgrades will be $295, otherwise $495
 (PC Week 04/15/92; 03/15/93).
Other OSes
PC-DOS 6.0: IBM's version of DOS 6.0.  It runs Windows much faster then DOS 
 6.0 due to faster file I/O and video handling (InfoWorld Feb 1, 93).
DR DOS 6.0: same as DOS 5.0 with some extras {like built-in data compression} 
 and memory management enhancements. Still has 640K/1MB barrier.  A later 
 version {Novell DOS} of this may use a version of the Mac finder and Apple 
 file management system (PC Week 12/14/92; InfoWorld Dec 14/92).
OS/2 2.0: Unix like features and unix like requirements; 8-16MB RAM,
 60MB {uses 17-33MB} hard drive, and 386dx CPU. This 32-bit multithreaded, 
 multitasking OS can address up to 4GB of RAM but has to use a fast swap file 
 to use more than 16 MB RAM on ISA systems using DMA {Direct Memory Access}. 
 IBM plans to use Taligent's OOPS in future versions of this 
 (InfoWorld Oct 26/92).
AIX:  IBM's UNIX system, planned to be a subset of PowerOpen and Taligent OS.
NeXTStep: GUI UNIX to provide NeXT features on IBM machines.  Beta out, final 
 version to be out by May 25, 1993.
Solaris OS for x86: a SunSoft port.  A 32-bit OS with symmetric 
 multiprocessing and multithreading, built-in networking capabilities with 
 tools to allow remote configuring and adminstration features, and 
 communication package.  Client: $795,  50 users server: $1,995, 1000s users
 server: $5,995.  Developer kits-software: $495, hardware: $195.
Mac 7.1 [working name: Star Trek]:  Apple had System 7.0 running off Intel 
 Chips and is looking at making a 7.1 version available for IBM 
 (ComputerWorld Nov 2/92; MacWeek 03/22/93). At present this is planned to run 
 on top of Novell's DR DOS, require a 486 or equivalent to run and that apps 
 will need to be recompiled (MacWeek 03/22/93).  Viewed as Novell's answer to 
 Windows NT.  The complexity of PC hardware set ups is one reason for slow 
 progress {This seems to Apple/IBM's way of leading to the PowerPC line out in 
 late 1993/early 1994 and Pink OS in late 1994-early 1995.}

PowerPC
Rumor-IBM will build its PowerPC 601 by late 1993 (InfoWorld June 8 & 15, 92; 
MacWeek 7/13/92; PC Week 3/15/93).  It will have MicroChannel bus and XGA 
video (Carl B Jabido), and will run native version AIX and Mac apps (PC Week 
3/15/93); there have been no comments on compatablity of DOS or Windows apps.
Apple's PowerPC 601 machine {Tesseract} is planned to be out Jan 24, 1994 and 
to have MC98601/50 MHz, 4/8MB RAM, a 2.8-Mbyte floppy drive and expected to 
sale near LC line prices {~$2000, down from projections of ~$3000 (MacUser 
9/92:146)}
(MacWeek 3/22/93).
PowerOpen [A/UX 4.0]: A 32-bit preemtive multitasking OS planned to run on
 PowerPCs and 68030/40 Macs (MacWeek 7/13/92).  Intel compatibility uncertain
 (See Mac 7.1 above).  Planned base requirements:  68030, 8MB RAM, 80MB hard
 drive (MacWeek 4/19/93). Rumor-ahead of schedule; COULD be out by mid 1993.
 Rumor-this could be the OS for IBM's PowerPC 601 which is due by late 1993.
Pink [Taligent OS]: Expecting delivery in 1994 (Wall Street Journal 1/12/92) 
 and may have some parts shipping in OS/2 and AIX in 1993 and Mac OS and 
 PowerOpen with the PowerPCs (MacWeek 01/25/93).
Windows NT: Possible port (MacWeek 04/05/93).  See IBM OS section for details.
Solaris OS: Version of this Sun Microsystems Inc UNIX OS to run on the
 Power PCs in 1994 (MacWeek 04/05/93).  One of the few OSes to directly state 
 that it will run Windows/DOS programs.  IBM OS section for details
NeXTStep: possible port see IBM OS section for details.

OS Number Crunching (Mel Park)
Mac
 Arithmetic is done in a consistent numerical environment {SANE or Standard 
Apple Numerics Environment}. Floating point numbers are 96 bits long when an 
FPU is present and 80 bits otherwise. Exceptions, such as dividing by zero or 
taking the square root of a negative number, do not cause an abort but are 
handled in a logically consistent manner. 1/0 produces the internal 
representation for infinity (INF).  1/(1/0) produces zero. The above treatment 
of 1/(1/0) occurs in an FPU-equipped machine even when SANE is bypassed and 
the FPU programmed directly.

IBM
 Floating point numbers are 80-bits with a hardware FPU, 64-bits when 
emulated.  The way they are handled is dependent on the coding of whatever 
compiler or assembler was used for a program. On older DOS complilers 
exceptions could cause program aborts; 1/0 and 1/(1/0) would abort to the DOS 
prompt at the point where they occured.  Most present compilers handle this 
better.  Result: there is little consistent handling of numbers between DOS, 
Windows and OS/2 programs nor between programs for just one OS.

Networking [Includes printing]
WYSIWYG printing can be a problem with either Mac of IBM machines especially 
if one sends TrueType fonts to a older style PostScript printer.
Mac
Hardware: Built-in LocalTalk network port and a built-in printer port.  
LocalTalk has moderate speeds (230.4 Kb/s) requires special connectors for 
each machine ($15 and up) and can be run off of either the printer port {to 
include very old macs} or the network port {standard today}.  Built-in 
Ethernet is becoming common but many older Macs require a PDS or Nubus card at 
about $150-$300 for each machine.  These cards provide three connectors and 
transceivers {thick, thin, and 10BaseT} for Ethernet.
The Macintosh Quadra family and some Centris models includes Ethernet 
interface on motherboard, with transceivers available. TokenRing has been a 
network option since 1989.
Software: AppleTalk {the suite of protocols} standard with Mac OS, which can 
use variety of media types.  AppleShare client software included with the OS 
as well and can connect to file servers such as Novell Netware, 3Com 3+Open, 
Banyan Vines, DEC Pathworks, Apple's AppleShare servers, System 7 File Sharing 
machines, and AFP servers running on variety of UNIX hosts.  MacTCP allows 
typical TCP/IP communications (telnet, ftp, NFS, rlogin).  A later version 
will have Unix X/Open Transport Interface (XTI) built-in by the end of 1993 
(MacWeek 04/12/93).  Third-party software to connect to NFS servers.  DEC 
Pathworks provides DECnet support.  Peer-to-peer file sharing software 
built-in to System 7.1 (See OS section).  Full server software is extra. 
Printing requires connection of the printer and the printer being selected in 
the chooser.  Changing printers is by selecting a different name in the 
chooser.  The same is true of connecting to servers.
Printing bugs:  Monaco TrueType font is different then the screen bitmap font.
 {QuickDraw QX is suppossed to fix this and similar problems.}

IBM  
Hardware: LocalTalk [not widely used], Ethernet,  and TokenRing.
Software: Novell Netware, Banyan Vines, DECNet, Windows/Work Groups, AppleTalk 
protocols, and AppleShare {subset of AppleTalk}.
Each of the MS-DOS networking schemes are, in general, totally incompatible 
with the others. Once you have chosen one, you are pretty much locked-in to 
that product line from then on.  Windows/Work Groups is a little more 
forgiving and removes some of this problem.  Novell Netware is the biggest, 
{~80 percent of the corporate market.} and in general is more powerful and 
offers better control/management/security than AppleShare, but it's also more 
complex to set up and manage.  This will change due to the use of the Mac 
finder and file management system by Novell. (PC Week 12/14/92 & 12/28/92;  
InfoWorld Dec 14/92; MacWeek 3/22/93)
Printing {Very OS dependent}
DOS: If it's a single user, then you plug the printer into the parallel port, 
 and don't worry about it {Tweeking may be needed with poorly written 
 software}.  Network Printing is not controlled by the system, but is mostly 
 implemented by the actual program, therefore performance varies from one 
 software program to the next.
Windows 3.x: supports standard drivers and can do a good job of showing "jobs" 
 in the print queue, but it always lists printers as "active"... even if they 
 are not.  This becomes a problem if there are several incompatible printers 
 on the same net, because there's no way for software to reliably determine 
 which printer is active right now.  Windows for Workgroups is more Mac-like 
 and intelligent about this.
OS/2: Mac-like; the os deals with printers, with apps making calls to the OS.
Printing bugs: due to poor programing some programs for all the above OSes do 
not have WYSIWYG printing.  This is the fault of the programs in question and 
not that of the OS involved.

Price issue: This is very dynamic with Mac providing more build-in features 
than IBM and IBM being more 'get only what you need' then Mac and price wars 
by both worlds.
The IBM machines' modualar nature prevents any kind of true hardware 
standarization, which in turn requires OSes and programs to be very complex to 
handle ALL the variation in hardware.  When one adds all the standard Mac 
hardware features to an IBM {built-in input/output sound support, SCSI, PDS,  
built-in monitor support, built-in networking, standard mouse interface, and 
NuBus 90 in higher machines} the Mac tends to be cheaper then an equivalent 
equipted IBM machine {Especially since some IBM monitors can be used with Macs 
which cuts some more of the Mac's cost (MacUser Aug 1992:158-176)}.
 Some prices using some of the info in this sheet and MacUser April 1993.
All Macs below come with a PDS slot, VRAM, and SCSI-1 built in.  Except where 
noted, monitor is extra and a built-in monitor interface is provided {no card 
needed except for 24-bit color display}.
IBM planned a $1,200 386SLC/25MHz model with a 60MB hard drive and color VGA 
monitor {~VRAM} (MacWeek 8/17/92) {sounds like a Color Classic without SCSI-1, 
sound support, built-in network support, FPU socket, built-in expansion to 
16-bit color, etc}.
Color Classic:  $1,389 - 030/16MHz with 16-bit data bus {~386sx/20MHz 
equivalent}, 4/80, FPU socket, and built-in monitor.
LCIII: $1,499 - 030/25MHz {~386dx/33MHz equivalent}, and 4/160.
Centris 610: $2,899 - 68LC040/20MHz {Depending on the program ~486sx/40 or 
~'486dx2sx'/20[40]MHz equivalent}, 8/230, built-in ethernet, 300i CD-ROM, a 
PDS/NuBus 90 slot and VRAM for 16-bit color.
Centris 650: 040/25MHz {Depending on the program ~486dx/50 MHz or 486dx2/50 
MHz equivalent} with a PDS and 3 NuBus 90 slots. $3,189 {ethernet, 8/80}; 
$3,559 {ethernet, 8/230}; $3,999 {ethernet, 8/230, CD-ROM, VRAM for 16-bit 
color}

Bibliography notes
'Vaporware' is available in the digest/vapor directory by FTP on sumex-
aim.stanford.edu [36.44.0.6] and was by Murphy Sewall {last issue: April 93.}
'Info-IBMPC Digest' back issues are available from wsmr-simtel20.army.mil in 
directory PD2:<ARCHIVES.IBMPC>
'Dictionary of Computer Terms 3rd ed.' (ISBM 0-8120-4824-5)

These are the facts as they were known to me on 4/15/93 and may be changed by 
new developments, announcements, or corrections.  Corrections to the 
information are welcome.
Please email corrections to 
CompuServe ID: 72130,3557
AOL: BruceG6069
Internet:  bgrubb@dante.nmsu.edu

Final note: Since there is NO comp.sys.ibm.pc.advocacy group this has been 
posted to the closest relevent groups {comp.os.ms-windows.advocacy, 
comp.os.os2.advocacy, and comp.sys.ibm.pc.misc}.  Also since some Mac vs IBM 
articles have been showing up in comp.sys.mac.hardware I have included that 
newsgroup in the posting. {Don't site the comp.sys.mac.* FAQ as a reason not 
to post to comp.sys.mac.hardware, since the FAQ itself does not follow 
internet guidelines, especially the de-facto "[all] the FAQs for a newgroup 
hierarchy should be posted to ALL newsgroups in the hierarchy" standard.}

"Eliminate the impossible and what ever remains, no matter how improbable,
is the truth" -- Sir Arthur Conan Doyle through Sherlock Holmes in The 
Adventure of the Beryl Coronet, The Adventure of the Blanched Soldier, Sign of 
Four and The Adventure of the Bruce-Partington Plans.