DOCUMENT ID:  1035-02

SYNOPSIS:     Hardware Setup and Differences Between X86 and SPARC

OS RELEASE:   2.1, 2.4, 2.5

PRODUCT:      Solaris x86, Solaris Sparc

KEYWORDS:     hardware setup difference system x86 sparc


DESCRIPTION:

Basic Differences Between X86 Machines and SPARCstations and hardware
setup. 


SOLUTION:

The x86 computer system runs the same instruction set and their buses
transport the same set of signals as on the SPARC systems, but there are
hundreds of adapter cards and motherboard configurations to account for
when installing on an x86 system.  The basic differences are described
in the following sections. 

BIOS Versus OpenBoot

When a PC (x86 machine) is powered on or when the reset switch is
pressed, the PC automatically executes code in ROM.  This code causes
the PC to run a series of self-test routines call POST.  POST routines
determine which hardware is present, verify that the hardware is
minimally functional, and perform initialization of that hardware.  This
is the same sequence of events that occurs on the SPARCstations. 
However, on the PC, the code in ROM is known as the BIOS (Basic
Input/Output System), whereas on SPARC systems it is known as OpenBoot. 

In addition to POST, the BIOS supplies a set of routines for controlling
and servicing the hardware in a common fashion regardless of who the
manufacturer is.  Thus it acts as a layer of abstraction that permits
the operating system and other stand-alone programs to be shielded from
some of the idiosyncrasies of a particular hardware implementation. 

In some PCs, an add-in card contains its own installable ROM BIOS which
is known as an "extension" to the system BIOS.  This add-on card is
located by a special signature during the primary bootup process. 
Unlike diskette or a hard disk.  The BIOS boot routine is automatically
invoked as the last part of a reset.  After executing the initialization
code for the extensions, the first sector from the boot device is copied
to memory and then executed.  If this sector does not contain proper
bootstrap code, the results are unpredictable.  In certain situations,
this can be detected because invalid data results and an error message
is issued. 

Disk Drive Setup

By default, floppy drive A is first checked for a boot diskette and then
hard drive C.  If the PC has both 3.5" and 5.25" floppy drives.  It may
not always be apparent which one is A and which one is B.  Unlike
SPARCstations, some x86 manufacturers permit the A and B drives to be
swapped simply by opening the cabinet and changing the connector the
drive is plugged into on the ribbon cable.  The other end of the cable
is connected to either the motherboard or the SCSI adapter. 

You can alter the defaults for booting by modifying the system setup
program.  The system setup program is a configuration utility supplied
by the system manufacturer in ROM BIOS. 

If the floppy drives are swapped by recabling, use the system setup
program to modify the settings of the A and B drives to match. 
Otherwise, the results of accessing files on those drives are
unpredictable. 

You can also use the system setup to disable the "shadow RAM" and the
"secondary cache".  All other options should remain as the factory
default values as described in the manufacturer's documentation. 

Configuration Methods

Unlike SPARCstations, x86 companies are configured by hardware
jumpering, software settings in memory, or a combination of both
methods. 

Configuring with Jumper Settings

A jumper is a small rectangular piece of plastic containing metallic
holes which fit over two pins and connects them electrically, similar to
closing a switch.  A jumper block has a label which can be a letter, or
some combination like J8.  A jumper can be a single pair of pins or as
many as a dozen laid out either horizontally or vertically. 

ISA boards should be checked thoroughly to verify that their hardware
jumpering is set to the factory defaults described in the manual that
came with the board.  This can be determined by comparing the positions
of the jumpers with those in the diagrams contained in the manual. 

Some ISA cards can also be configured by software, provided the jumpers
are set correctly.  For example, the SCSI host adapter board has a
jumper setting to indicate whether it or the motherboard is controlling
the floppy drive. 

Configuring with Software Settings

EISA boards do not require hardware jumpering.  Instead they use a
generic configuration program which comes on diskettes supplied by the
system manufacturer.  It is necessary to run this program after EISA
boards are added, removed, or repositioned in a different slot. 
Although the overall function of this utility has been standardized,
there are many implementations - each of which presents its own user
interface screens and menus. 

Unfortunately, there is no a single way to invoke the program.  Some
manufacturers put it on a bootable DOS diskette and start it up
automatically from the AUTOEXEC.BAT script.  Others require that DOS be
running first before the EISA configuration diskette is inserted in the
drive. 

In either case, this utility operates by reading files describing the
particular piece of hardware and what can be changed on it.  The naming
convention for these files is !vvvpppp.CFG where vvv is an alpha vendor
ID and pppp is a numeric product ID.  The contents of these files are in
ASCII and they contain a series of nested keyword=value pairs describing
not only EISA add-on cards, but also ISA cards, and the system
motherboard. 

Even though the ISA cards cannot be configured with this program, the
program can still detect conflicting options among the boards whose
files have been chosen through its menu interface and whose defaults may
have been modified.  Therefore, you should run the configuration program
before any ISA board changes are made. 

Since some boards are too complex to be adequately described by the
syntax of the EISA configuration program, executable .OVL files are
provided.  If the EISA utility is run many times from the same diskette,
it can fill the disk with files, since it saves the previous
configuration in the event you want to restore a former setting.  In
this case, it is easiest just to use a new diskette. 

Hardware Terminations

The SCSI adapter board has connectors for both an external and an
internal cable.  The external cable will normally connect to a CD,
second disk, or tape drive while the internal cable will be attached to
the primary disk (i.e.  target 0).  If multiple external devices are
present, they are "chained" together in series.  Regardless of the
number of external devices, terminate the last one on the chain with a
small plug containing resistors. 

There are also terminating resistors on the disk at the end of the
internal cable.  The SCSI bus requires termination at both ends, only. 
Having one end unterminated, or supplying extra termination somewhere in
the middle, can cause unpredictable results. 

To check this, remove the card and look for 3 flat resistors directly
under the internal cable connection.  If they are found, use tweezers or
a needle-nose pliers to remove the resistors from the board.  If the CD
drive was the only external device, and if it is no longer needed after
installation, then to avoid having to put the resistors back into the
board, place a termination plug in the external SCSI connector. 


DATE APPROVED: 09/18/95