The Aspen group of companies that last August boldly set out to define a broad set of 64-bit Unix application programming interfaces, has handed over an agreed, if limited, set of proposals to Reading, Berkshire-based X/Open Co Ltd. Included is a four-page document said to describe around 20 changes that would be required for the 32-bit Spec 1170 single Unix specification to support 64-bit applications. The changes remove data size dependencies and expose 32-bit code for 64-bit processing, and X/Open will be feeding the changes into Spec 1170 as error changes. After a rather heated debate, it is said, the Aspen working group also agreed to implement a common 64-bit programming model, LP64, for consistent representation of C language datatypes and for describing, among other things, how pointers are to be used in code. Several companies, including Digital Equipment Corp and Silicon Graphics Inc, already support particular 64-bit data-type models, but in the end LP64 supporters such as Silicon Graphics triumphed over proponents of the alternate ILP64 and LLP64 models that were also under consideration. Silicon Graphics said that although LP64 requires a greater programming effort than other models, it results in more robust applications. LP64 will be submitted to X/Open’s fast track specification process at the organization’s meeting next month. The Aspen companies also agreed on a common set of extensions to the Posix Threads interface and dynamic linking interfaces to support the emerging class of extensible self- configuring applications based upon ELF. These, along with Posix application programming interfaces for software installation, support for files larger than 2Gb from 32-bit environments and user group management to improve multi-vendor systems management, are being turned over to X/Open to put through its working groups. X/Open says it would be wrong to characterize what is still missing as simply 32-bit work that doesn’t lend itself to 64-bitness or things that Aspen merely left on the cutting-room floor. X/Open hopes to complete work on the second version of its single Unix specification (which may or may not retain the same name) including the 64-bit work that it us taking over from Aspen by the end of this year. If it does, it expects to see branded products two years from now. Although Aspen won industry-wide endorsement when the initiative was announced last August, more than a few vendors were sidelined from real participation. As a result, many of them are expected to handle other calls for endorsement – including any for the Hewlett-Packard-Santa Cruz Summit 3DA 64-bit Unix effort – with less blind enthusiasm. In the end, the scale of the problem that Aspen set out to solve exceeded what could be achieved through its Common Open Software Environment-style ad hoc process. The need actually to deliver on some of its promises meant that it had to go now with what it had achieved, and turn the rest over to X/Open.