AT & T have introduced a new memory baseboard and simm's for the NCR3-3555. They are designated the following mec identities:

• NCR3-3555-dmbb4(128MB) - memory baseboard
• NCR3-3555-dmem-simm - simms

• Ensure that the customer has two verified filesaves before commencing the installation.
• Always ensure full esd precautions are employed when handling
• Static sensitive equipment.

(tech serv ref 39/01)

Installation instructions for NCR3-3555 disconnect memory baseboard version 2 (dmbbb4) and dsimm submodules.

Release 2.03.01 or later of the at&t Unix v.4 mp-ras operating system, nfs, oe, mu oe, or client/server foundation oe is required for all of the 35xx Unix base models. 345x and 35xx nt server base models will require microsoft windows nt advanced server version 3.51. In addition the compatibility package pkern 203 ver 95.04.14 or later must be installed on 2.03.01. If Unix 3.00 or greater is installed, the compatibility package is not required. These instructions were written to document the installation of both the disconnect memory baseboard version 2 (dmbb4), and also the double density flex/rigid simm (fsimm) submodules. Use the sections that apply to the actual installation at hand.

The 2GB disconnect memory baseboard version 2 provides a system memory implementation of the system 3000 voyager architectural specification. The dmbb4 is a dual port, dual interleave dram memory that provides the memory based coherency required by voyager. The dmbb4 utilizes 4-bit dram technology versus the dmbb1 1-bit technology. The module can be operated in one-way, two-way, or four-way interleaved mode. There are strict guidelines which must be followed when installing simms to obtain the best possible performance. Simm submodules installed on a magellan memory baseboard (mMBb1), or the disconnect memory baseboard (dmbb1) are not compatible with the dmbb4, or vice-versa. The simms designed for the dmbb4 are physically larger than simms designed for the dmbb1. However, it is possible to mix a mMBb1, or a dmbb1 with a dmbb4 in the same unit using required software and firmware. If a mMBb1 is installed in the same unit with a dmbb1 or dmbb4, there is a maximum memory size restriction of 2GB total memory. The dmbb4 module supports the functionality of the magellan memory baseboard mMBb1 as well as extended functionality including disconnect memory read cycles, memory expansion to 2GB per module, and the hardware controlled module level dram self-test. Interleave capacities supported are 16MB, 32MB, 64MB, 128MB, 256MB, 512MB, 1GB, and 2GB using the 4m x 24, or 16m x 24 simms. The dmbb4 is designed to support up to 4096MB of four-way interleaved dram system memory when two boards, fully populated with 32m x 24 dram flex/rigid simms are installed in the NCR3-3555 unit. The maximum current draw for a single dmbb4 system is 10.3 amperes. In a system with 2 dmbb4's the maximum current draw is 15.9 amperes total for both modules.

• first, determine the current release of firmware and software installed in the unit. Also determine if an additional power supply, available in at&t kit no. 4850-k610 will be needed before installing the new memory baseboard. Use the power supply calculation guide in figure 4 and figure 5 to determine if an extra power supply is required. If newer versions of software and firmware are needed obtain the required versions and install by referring to the system 3000 user manuals. Once this has been done, perform an orderly shutdown of the system.

• turn the front panel switch off

• open both the ac main and battery circuit breakers located at lower rear of the unit behind the rear doors.

• disconnect the ac power cord from the power source. Open the front doors. Remove both the front and rear emi safety covers by loosening the captive fasteners and lifting the panels upward. If an additional power supply is required, install it at this time by referring to the instructions included with the power supply kit.

• if you are upgrading an existing memory baseboard, locate it at this time and remove it from the unit. If you are adding simm submodules to a new dmbb4 being added to the unit or to an existing dmbb4, locate it at this time. To remove a memory baseboard from the unit, grasp both ejector tabs and place the module onto an esd protected surface. Refer to figure 6 & 7 for memory slot locations. If you are simply adding a dmbb4 that is already populated with simms, then skip to step Point 1.

• if you are performing an upgrade of existing simm submodules, or adding extra simm submodules to increase the memory capacity then determine the best way to configure the submodules onto the dmbb4 to obtain maximum performance from the interleave memory. Please refer to figure 2 & 3. There are a number of guidelines to follow to accomplish this:
  
  
  • dmbb4 supports two dram interleaves. Each interleave is divided into two physical banks, bank o and bank 1, of seven simm sockets per bank. dmbb4 requires that all simms installed within an interleave must be the same capacity dram simms and should contain the same population. Upgrades to memory are accomplished by the addition, or replacement of the simms, or fsimms on a dmbb4. Refer to the valid memory configuration chart in figure 2 for simms, and to the chart in figure 3 when installing fsimm submodules onto the dmbb4.
    
    
  • Rule 1) all dram simms installed in a given physical interleave must be the same capacity. That is all simms must be 4m x 24, or all simms must be 16m x 24. This is true whether one or both banks of the physical interleave are populated.
    
    
  • Rule 2) intermixing of 32m x 24 fsimms and 16m x 24 simms on the same baseboard is not allowed under any circumstances.
    
    
  • Rule 3) for best system performance, 4-way interleave is preferred over 1-way interleave.
    
    
• Other points to remember:
  
  
  • in order to obtain maximum system performance, every physical interleave available in the system should be populated with dram simms. If one dmbb4 is present, then both physical interleaves should be populated.
    
    
  • if two dmbb4's are present, then all four interleaves should be populated. This is true even if only one bank of each physical interleave may be populated.
    
    
  • if a mMBb1 is present in the same unit along with a dmbb1 or dmbb4, there is a maximum memory size restriction of 2GB. Total memory size cannot exceed 2GB in this situation.
    
    
  • dmbb1 allows the 1-way and 2-way interleaving of physical interleaves with the same amount of installed memory. Utilizing 4-way interleave requires two memory baseboard
    
    
• installing/removing simm or fsimm submodules on the dmbb4:
  
  

  • The simm submodules are keyed and it is very important to observe the proper orientation when being inserted into a connector on the memory baseboard. When installing the simm submodules, locate the small notches on the "finger' edge of the submodule and align with the corresponding tabs in the connector. Once aligned, press the submodule in firmly until both ejector tabs lock it in place. Repeat this step until all simm submodules are installed.

  • To remove simm submodules locate the small ejector tabs on either end of a simm connector and press outward, away from the middle of the socket. This should eject the submodule from the connector so it can be removed from the baseboard. Repeat this step until all simm submodules are removed.
    
    
• determine which memory slot this baseboard is going to be installed in. There are only two memory slots in the unit. Mem2 which is located in the front and mem1 which is located in the rear of the unit. Refer to figure 6 & 7 for memory baseboard slot locations. If a memory baseboard module was removed from one of these two memory slots to upgrade the submodule's, it will be best to reinstall it into its original slot so as to maintain the same system configuration as before.

• (^{Point 1}) install the memory baseboard module by first aligning the card edge with the card guides in the card rack. Slide the baseboard module in while holding horizontal. Once the module makes contact with them backplane, push the tabs inward towards each other to seat the module into the system baseboard connector.

• replace the safety cover and tighten the captive fastener screws.

• reconnect the ac power cord to the power source and close both the ac main and battery circuit breakers.

• close the front and rear doors.

• turn the front panel power switch on

The system should detect any changes in memory size, or a different baseboard (if it was replaced) during the start-up process. Refer to the addendum on figure 3 to determine dump and swap sizes for the root disk device. If any errors occur, refer to the system 3000 user's manuals.

From root run memsize to check the system "sees" all the memory.

No specific recording action.

Complete all normal documentation