AST RESEARCH, INC.       INFORMATIONAL BULLETIN # 0014       09/24/96 
 
 
 
TITLE:  Configuration Tips: PCI, Manhattan S
 
 
SUMMARY 
 
   This bulletin has been prepared to assist customers with the 
   selection and installation of PCI devices in their Manhattan S/6200
   and Commerce Pro servers. 
   
   Most of the information is generally applicable to PCI devices and
   is not specific to any version of PCI specifications. Some
   information is specific to the Manhattan S/6200 and Commerce Pro 
   servers. In these cases, the difference will be noted.
   
   This bulletin provides information related to the following systems:
   501832 and 503076.    
 
 
NOTES 
 
   BACKGROUND
   
   The Manhattan S/6200 and Commerce Pro servers are designed to 
   comply with the industry standard PCI bus. This bulletin provides 
   installation tips that will assist with selecting and installing 
   PCI adapters and help to avoid configuration issues.
   
   Generally, configuration issues with PCI devices are caused by 
   one or more of the following problems:
   
   1. PCI Adapters which do not completely support the PCI
      specification.
   
   2. Differences between interpretations of the PCI
      specification by device designers.
      
   3. Additional features and enhancements added by device
      manufacturers, which do not properly interact with
      other standard PCI devices.
   
   4. Mixing PCI and ISA adapters in the same system.
   
   5. Limitations within the PCI specification as to the 
      number of IRQ lines available to PCI devices.
   
   Following the checklist and guidelines below will minimize the 
   above factors and resolve the largest share of PCI configuration issues.
   
   MANHATTAN S/6200 AND COMMERCE PRO REQUIREMENTS
   
   The Manhattan S/6200 and Commerce Pro servers are designed for 
   use with three types of adapter boards:
   
   1. 32-bit, 5 volt PCI adapters
   2. 32-bit EISA adapters, and 
   3. 16-bit ISA adapters.
   
   The PCI bus is comprised of the top six adapter slots in the 
   system. There are two PCI busses in the system, connected 
   together by a PCI Bridge controller chip. The top two PCI slots 
   are located on the Primary PCI bus, which is sometimes referred 
   to as "ahead" of the PCI bridge. The next four PCI slots are 
   located on the Secondary PCI bus, which is sometimes referred to 
   as "behind" the PCI bridge. Keep the slot location in mind when 
   installing PCI devices, because some adapter device drivers do 
   not support PCI Bridges. If an adapter is not working correctly 
   when installed on the Secondary PCI bus, try to install the 
   adapter on the Primary PCI bus. If the adapter works properly on 
   the Primary PCI bus, contact the manufacturer of the adapter and 
   obtain a driver that supports PCI Bridges.
   
   Also consider that some of the PCI slots share PCI Interrupt 
   Request Lines (PCI IRQs) with other PCI slots in the system. The 
   PCI specifications allow system manufacturers to share PCI IRQs 
   with multiple PCI slots. However, some adapters do not operate 
   properly when they are forced to share an IRQ with another 
   device. Typically, obtaining a later device driver from the 
   manufacturer will resolve these problems, because most adapter 
   designers now ensure that their drivers support these 
   configurations. The table below lists the slots which share PCI 
   IRQs in the Manhattan S/6200 and Commerce Pro servers. If a PCI 
   device is not working correctly, try to install it in a slot that 
   does not share its PCI IRQ. 
   
   Pre-Assigned IRQ Settings in Manhattan S/6200 and Commerce Pro
   
      Slot Number       Shares IRQ with Slot Number
           1                   5
           2                   6
           3                   Not shared
           4                   Not shared
           5                   1 
           6                   2
   
   
   PCI adapters may be available in 5 volt, 3.3 volt, and universal 
   (supports both the 5 volt and 3.3 volts) variations. Both 5 volt 
   and universal adapters can be physically installed in the 
   Manhattan S/6200 and Commerce Pro servers. A 3 volt adapter can 
   not be installed. Ensure that all PCI adapters are either 5 volt 
   or universal.
   
   NOTE: At the time this bulletin was authored, no 3.3 volt or 
   universal adapters were readily available on the market.
   
   CHECKLIST
   
   When selecting PCI adapters, always ask the following questions:
   
   1. Does the PCI adapter operate correctly in a 32 bit, 
      5 volt PCI bus slot?
      
      These are the two primary specifications that should 
      be considered when selecting a PCI adapter. A PCI 
      adapter that will not operate in a 32-bit, 5 volt PCI 
      slot will not function in the system.
   
   2. Does the adapter work on both sides of a PCI - PCI 
      bridge?
      
      As indicated above, some adapters may not work
      properly "behind" the PCI Bridge. If the adapter will 
      not function behind the PCI bridge, it may only be 
      installed in PCI slot number 1 or 2. Check with the 
      adapter vendor to ensure that the device will operate 
      properly in a PCI bridge environment. 
   
   3. Does the adapter support PCI IRQ sharing?
      
      If the PCI adapter does not support PCI IRQ sharing, 
      then it may only be installed in PCI slot number 3 or 
      4. These slots do not share their PCI IRQ. Check with 
      the adapter vendor to ensure that the PCI device 
      supports sharing of PCI IRQs.
   
   As a troubleshooting and performance aid, it is best to share PCI 
   IRQs of the same device type and manufacturer. The designer of 
   the device, when writing a driver that shares IRQs, will have the 
   most knowledge about the manner is which their own devices behave 
   in a shared environment. AST also suggests that identical 
   adapters be used in a shared PCI IRQ environment. A driver could 
   operate incorrectly if two adapters are similar, but not 
   identical. 
      
   CONSIDERATIONS FOR EISA DEVICES
   
   There are three slots provided in the system for EISA bus 
   adapters. These adapters are configured through the AST System 
   Configuration Utility.
      
   When installing an EISA adapter into the system, always configure 
   the EISA adapter prior to installing PCI adapters. EISA adapters 
   use "static" resources, meaning that once configured through the 
   AST System Configuration Utility, they will not change without 
   re-running the utility. The EISA adapter's resources will then be 
   "sensed" by PCI devices. The PCI device will then attempt to 
   avoid conflicts with the EISA adapter.
      
   As a general rule, PCI devices should not be configured to share 
   resources with EISA devices. While there may be cases when such a 
   configuration is possible, AST does not suggest to configure the 
   system in this manner.
   
   CONSIDERATIONS FOR ISA LEGACY DEVICES
   
   An ISA Legacy device is a 16-bit ISA adapter, which is not 
   Plug-and-Play (PnP) capable. This type of device is not aware of 
   other devices in the system and can not be reconfigured by the 
   AST System Configuration Utility. Typically, an ISA Legacy 
   adapter will be configured through switches or jumpers on the 
   adapter board, or through a special configuration utility from 
   the device manufacturer.
      
   Legacy ISA adapters are the most troublesome technology to mix in 
   a system with EISA and PCI devices, because of the inflexibility 
   of the ISA adapter and the inability of EISA and PCI devices to 
   "sense" the existence of ISA legacy adapters.
      
   In order to avoid conflicts, you must know the resources used by 
   the ISA adapter. If you do not know which system resources an ISA 
   adapter uses, contact the manufacturer of the adapter before 
   installing the adapter in the system.
   
   Once you have established the resources that will be used, 
   install the ISA Legacy adapter in the system prior to installing 
   any EISA or PCI devices. Run the AST System Configuration Utility 
   and manually add the ISA adapter to the system and lock its 
   resources. This can be accomplished by either creating a new .CFG 
   file in the AST System Configuration Utility, or by adding a .CFG 
   file from the manufacturer if one is available.
   
   NOTE: It is important to understand that by adding information to 
   the AST System Configuration Utility about ISA Legacy adapters, 
   EISA and PCI adapters will become "aware" of the existence of the 
   ISA adapter in the system. However, changing the information in 
   the utility program will not change the actual configuration of 
   the ISA Legacy adapter. Additionally, if the information supplied 
   to the utility is incorrect, the EISA and PCI devices will be 
   "aware" of the wrong information.
   
   After adding the ISA adapter information to the AST System 
   Configuration Utility, add EISA adapters and run the AST System 
   Utility again. Finally, install the PCI devices. Adding devices 
   in this order will ensure the orderly assignment of resources to 
   the PCI devices in the system.
   
   CONSIDERATIONS FOR PLUG-AND-PLAY ISA DEVICES
   
   Plug-and-Play (PnP) ISA devices are similar to ISA Legacy 
   devices, with the addition of "dynamic" resource configuration. 
   Resources for these devices are typically configured every time 
   the adapter senses a change in the system's resource. Typically, 
   the number of system resources variations is limited to a 
   pre-selected group.
     
   If an ISA board is operating as a PnP device, it will configure 
   itself to avoid conflicts with other devices in the systems. 
   However, if the PnP features of the ISA device are disabled, the 
   device will operate as a standard ISA legacy device and will 
   exhibit any of the problems noted above concerning ISA legacy products.
      
   Generally, ISA PnP resources can be locked by a utility supplied 
   by the manufacturer. Contact the device manufacturer to obtain 
   any utilities that can be used to lock resources and prevent 
   dynamic reconfiguration. After the ISA PnP configuration has been 
   locked into place, follow the suggestions above, treating the ISA 
   PnP device as if it were an ISA Legacy device.    
 
 
TAN N/A 
 
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