2166 Quayle

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Replacing VAXen with VAX Emulation Stanley F. Quayle, P.E. President Quayle Consulting Inc.

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Replacing VAXen with VAX EmulationPresented at HP World 2003

Transcript of 2166 Quayle

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Replacing VAXen with VAX Emulation

Stanley F. Quayle, P.E.President

Quayle Consulting Inc.

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HP World 2003 Solutions and Technology Conference & Expo page 204/12/23

Session goals

Whether VAX emulation makes sense

How to choose the best emulator and platform

How to get started

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HP World 2003 Solutions and Technology Conference & Expo page 304/12/23

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?

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HP World 2003 Solutions and Technology Conference & Expo page 404/12/23

Wine, FreeVMS, and ACCELR8

RealHardware

CHARN-VAX

Host OS

Application

Layered softwareSystem libraries

Operating System

Application

System libraryinterface routines

Host OS

Host CPU(s)

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HP World 2003 Solutions and Technology Conference & Expo page 504/12/23

How hardware emulation works

RealHardware

CHARN-VAX

Host OS CPU(s)

Application

Layered softwareSystem libraries

Operating System

Application

Layered softwareSystem libraries

Operating System

Host OS

Emulator

Host CPU(s)

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HP World 2003 Solutions and Technology Conference & Expo page 604/12/23

The emulator task

CPUEmulation

Disk controller

disk

virtual disk

virtual disk

tape image

Tape controller

Clock Serial ports

SystemConsole

SerialDevices

EthernetMemory

External SCSITape & Disk

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HP World 2003 Solutions and Technology Conference & Expo page 704/12/23

CPU emulation

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

“TSTL XYZ”

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HP World 2003 Solutions and Technology Conference & Expo page 804/12/23

The emulator task

CPU

Emulation

Disk controller

disk

virtual disk

virtual disk

tape image

Tape controller

Clock Serial ports

SystemConsole

SerialDevices

EthernetMemory

External SCSITape & Disk

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HP World 2003 Solutions and Technology Conference & Expo page 904/12/23

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

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HP World 2003 Solutions and Technology Conference & Expo page 1004/12/23

Available emulators

Open-Source– SIMH– TS-10– Others

Freeware– PicoVAX

Commercial Product– CHARON-VAX

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HP World 2003 Solutions and Technology Conference & Expo page 1104/12/23

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

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HP World 2003 Solutions and Technology Conference & Expo page 1204/12/23

Evaluating the current system

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

Major Items to Check

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HP World 2003 Solutions and Technology Conference & Expo page 1304/12/23

Evaluating the current system

VMS version

Layered product versions

Application

Major Items to Check

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HP World 2003 Solutions and Technology Conference & Expo page 1404/12/23

Evaluating the current system

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”

Risky areas

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HP World 2003 Solutions and Technology Conference & Expo page 1504/12/23

Evaluating the current system

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

There Be Dragons Here

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HP World 2003 Solutions and Technology Conference & Expo page 1604/12/23

Special hardware: Q-bus

PCI bus Q-bus rackCable

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HP World 2003 Solutions and Technology Conference & Expo page 1704/12/23

Choosing the host platform

Alpha OpenVMS– Unquestionable stability

Linux– Inexpensive

Windows– Inexpensive– Q-bus support– “Industry standard”

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HP World 2003 Solutions and Technology Conference & Expo page 1804/12/23

Sizing the host platform

Server-class– As fast as possible

Memory– More with DIT

Processor– Dual processors

Disk– SCSI

Network– Separate network adapter

“You can’t have too much”

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HP World 2003 Solutions and Technology Conference & Expo page 1904/12/23

Performance

Sources: HP and Software Resources International S.A.

05

101520253035404550

CPU model - VUPs (VAX Unitof Performance)

MicroVAX II

VAX 11/780

VAX 3100 model 80

VAX 4000, model 500A

VAX 4000, model 700A

VAX 7000, model 710

CHARON-VAX/XM on dual AMD 1.6 GHz

CHARON-VAX/Industrial on 2GHz Intel

CHARON-VAX/AXP on 1 GHz Alpha EV68

CHARON-VAX/XM Plus on 1.4 GHz dual CPU Intel

CHARON-VAX/XM Plus on dual AMD MP2100+

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HP World 2003 Solutions and Technology Conference & Expo page 2004/12/23

Disk migration

Direct disk access– SCSI? Just plug it in!

Cluster

Network– COPY or COPY/FTP– BACKUP– MKIMAGE– Poor Man disk driver

Tape

Serial

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HP World 2003 Solutions and Technology Conference & Expo page 2104/12/23

Backup strategies

Tape

Network– TCP/IP to host– NFS

Host– Disk images offline– Disk images online– SCSI disks

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HP World 2003 Solutions and Technology Conference & Expo page 2204/12/23

Write a plan

Disk migration

Backup scheme

Necessary updates

Test– Connectivity– Application– Limited user access

Going live

Backout plan

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HP World 2003 Solutions and Technology Conference & Expo page 2304/12/23

Post-migration

Hardware support

Software support

System administration support

New versions

And they lived happily ever after…

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