Replacing VAXen with VAX Emulation
Stanley F. Quayle, P.E. President Quayle Consulting Inc. Session goals Whether VAX emulation makes sense How to choose the best emulator and platform How to get started
08/27/2003 HP World 2003 Solutions and Technology Conference & Expo page 2 What about porting? Do you have the design documentation? Do you have all the source code? – What about DECmigrate (OMSVA)? – VAX SCAN, Dibol, LISP, OPS5, RPG Operating system dependency? Hardware dependency? Target platform – Can code really be reused? – What about stability? Can you validate the result?
08/27/2003 HP World 2003 Solutions and Technology Conference & Expo page 3 Wine, FreeVMS, and ACCELR8
Application Application Layered software System libraries System library Operating System interface routines
CHARN-VAXHost OS Real Hardware HostHost CPU(s) OS
08/27/2003 HP World 2003 Solutions and Technology Conference & Expo page 4 How hardware emulation works
Application Application Layered software Layered software System libraries System libraries
Operating System Operating System
CHARN-VAXEmulator Real Host OS Hardware Host OS HostCPU(s) CPU(s)
08/27/2003 HP World 2003 Solutions and Technology Conference & Expo page 5 The emulator task
disk Memory Ethernet
CPU Disk controller virtual disk Emulation Tape controller
Clock Serial ports virtual disk
tape image
System Serial External SCSI Console Devices Tape & Disk
08/27/2003 HP World 2003 Solutions and Technology Conference & Expo page 6 CPU emulation “TSTL XYZ” Retrieve state information from internal registers Fetch the instruction from memory Decode the operation to be performed Retrieve inputs from memory as needed Perform the operation Write results to memory as needed Update internal registers with the new state
08/27/2003 HP World 2003 Solutions and Technology Conference & Expo page 7 The emulator task
disk Memory Ethernet
CPU Disk controller virtual disk Emulation Tape controller
Clock Serial ports virtual disk
tape image
System Serial External SCSI Console Devices Tape & Disk
08/27/2003 HP World 2003 Solutions and Technology Conference & Expo page 8 Cost versus benefit The high cost of downtime – Customer impact – “Above the Fold” on Wall Street Journal – Data Loss Saving money on maintenance – It’s cheap to replace a PC – Limited support vendor choices – Hardware support for some VAXen is unavailable Improved performance
08/27/2003 HP World 2003 Solutions and Technology Conference & Expo page 9 Available emulators Open-Source – SIMH – TS-10 – Others Freeware – PicoVAX Commercial Product – CHARON-VAX
08/27/2003 HP World 2003 Solutions and Technology Conference & Expo page 10 Open source or commercial? Open Source – Free: Can be downloaded from the Internet, including source code – User-extensible CHARON-VAX – Certified by HP as being a true emulation of a VAX – Supports Q-bus hardware – Dynamic Instruction Translation – Training, installation, configuration, migration, and support are available
08/27/2003 HP World 2003 Solutions and Technology Conference & Expo page 11 Evaluating the current system Major Items to Check CPU usage, memory size, number of users/processes Network – Protocols: DECnet, IP, LAT, cluster, IEEE 802 – DECwindows – Connections Disk drives: size, type, shadowing Tape drives
08/27/2003 HP World 2003 Solutions and Technology Conference & Expo page 12 Evaluating the current system Major Items to Check VMS version Layered product versions Application
08/27/2003 HP World 2003 Solutions and Technology Conference & Expo page 13 Evaluating the current system Risky areas Serial lines – Terminal servers – VAX serial lines • Console • Modem – H3104, DHV-11, etc Licenses – Network MAC address as “key” – CPU characteristics as “key” – VMS license requirements vs. emulated system – “It works” vs. “Is it legal”
08/27/2003 HP World 2003 Solutions and Technology Conference & Expo page 14 Evaluating the current system There Be Dragons Here Operating systems – NetBSD – Digital Unix – AT&T System V – VAXELN Special hardware – Bus: CI, M-bus, SBI, Turbochannel, UNIBUS, VAXBI, XMI – Disk interface: MASSBUS, SDI, ST-506 (MFM) – Some hope for: DSSI, Q-bus
08/27/2003 HP World 2003 Solutions and Technology Conference & Expo page 15 Special hardware: Q-bus
PCI bus Cable Q-bus rack
08/27/2003 HP World 2003 Solutions and Technology Conference & Expo page 16 Choosing the host platform Alpha OpenVMS – Unquestionable stability Linux – Inexpensive Windows – Inexpensive – Q-bus support – “Industry standard”
08/27/2003 HP World 2003 Solutions and Technology Conference & Expo page 17 Sizing the host platform “You can’t have too much” Server-class – As fast as possible Memory – More with DIT Processor – Dual processors Disk – SCSI Network – Separate network adapter
08/27/2003 HP World 2003 Solutions and Technology Conference & Expo page 18 Performance
50 MicroVAX II 45 VAX 11/780
40 VAX 3100 model 80
35 VAX 4000, model 500A 30 VAX 4000, model 700A 25 VAX 7000, model 710 20 15 CHARON-VAX/XM on dual AMD 1.6 GHz 10 CHARON-VAX/Industrial on 2GHz Intel 5 CHARON-VAX/AXP on 1 GHz Alpha EV68 0 CHARON-VAX/XM Plus on 1.4 GHz dual CPU Intel CPU model - VUPs (VAX Unit of Performance) CHARON-VAX/XM Plus on dual AMD MP2100+
Sources: HP and Software Resources International S.A.
08/27/2003 HP World 2003 Solutions and Technology Conference & Expo page 19 Disk migration Direct disk access – SCSI? Just plug it in! Cluster Network – COPY or COPY/FTP – BACKUP – MKIMAGE – Poor Man disk driver Tape Serial
08/27/2003 HP World 2003 Solutions and Technology Conference & Expo page 20 Backup strategies Tape Network – TCP/IP to host – NFS Host – Disk images offline – Disk images online – SCSI disks
08/27/2003 HP World 2003 Solutions and Technology Conference & Expo page 21 Write a plan Disk migration Backup scheme Necessary updates Test – Connectivity – Application – Limited user access Going live Backout plan
08/27/2003 HP World 2003 Solutions and Technology Conference & Expo page 22 Post-migration And they lived happily ever after… Hardware support Software support System administration support New versions
08/27/2003 HP World 2003 Solutions and Technology Conference & Expo page 23 Interex, Encompass and HP bring you a powerful new HP World.