Risks vs. Benefits of VAX/Alpha Emulation

This document, "Risks vs. Benefits of VAX/Alpha Emulation," presented at OpenVMS Bootcamp 2010, explores the advantages and disadvantages of emulating VAX and Alpha systems. The presentation outlines the goals of emulation, which include identifying suitable candidates for emulation, preparing for and validating the migration process, minimizing migration time, and effectively communicating the value of an emulation solution.

The document highlights that virtual systems are becoming increasingly common and lists various benefits of emulation, such as improved uptime and reliability, cost savings, faster applications, better integration into data center designs, and preservation of existing application investments. It also details scenarios where emulation is not advisable, including systems dependent on precise instruction timing, those with unique or "magic" hardware, equipment lacking modern interfaces, life-support applications, and situations where original system media is inaccessible or validation requirements are impossible to meet.

The presentation identifies good candidates for emulation as systems where emulators can effectively map modern hardware to recognized network connections, serial ports, disks, and tape drives. Conversely, risks include imperfect replication of the original system, emulator or host system failures, a lack of understanding of the solution by administrators, and customers attempting to cut costs by using unsuitable hardware or software configurations.

The document emphasizes the importance of collaboration between emulation providers and customers to determine if emulation is the best solution, suggesting alternatives like VEST/AEST and stressing that emulation is just one tool among many. It also provides guidance on preparing for emulation, including evaluating software licenses, developing a validation plan, and conducting proof-of-concept migrations. Strategies for minimizing migration time, such as copying only necessary data and utilizing parallel streams, are also discussed.

Finally, the presentation reviews various emulator choices for VAX systems, including SIMH, CHARON-VAX, and NuVAX, and for Alpha systems, such as CHARON-AXP and Avanti. It also mentions free Alpha emulators like PersonalAlpha and FreeAXP. The importance of demonstrating the value proposition of emulation over its cost is also stressed.