For only the second time since Big Blue entered the Unix market for real in February 1990 with the launch of the RS/6000 line of workstations and servers, the company is letting customers who use its Power-based servers take a future AIX release for a test drive in an open beta program.

The AIX 7 open beta, which launches today, gives customers a download of the binaries in a DVD ISO image that they can burn onto media and install on the last several generations of Power machines.

You can get the AIX 7 code here. AIX 7 will run on any machine based on the PowerPC 970 (remember that one, which was used in the initial IBM blade servers?) as well as on pSeries, System p, and Power Systems machines that employ Power4, Power4+, Power 5, Power5+, Power6, Power6+, and Power7 chips. (Presumably any of the iSeries and System i machines, which use IBM's OS/400 and i proprietary operating systems, that supported AIX inside logical partitions can also run the AIX 7 beta code, too, but IBM doesn't say this.)

The main thing, says Jay Kruemcke, AIX marketing manager within IBM's Power Systems division, is that customers can't run the code in production environments - in fact, the download agreement prohibits this, no doubt to absolve IBM of any responsibility in case someone uses AIX 7 in production.

In addition to letting Power Systems customers get their hands on the AIX 7 code, IBM let loose some of the details on the future AIX above and beyond what El Reg has already told you about the release, which is also called AIX 7.1 just to be confusing. AIX 7 will support a single system image that spans 256 cores and 1,024 threads and perhaps as much as 8 TB of main memory, which is four times the iron that was supported by the current AIX 6.1 release.

IBM says that AIX 7 will be binary compatible with the prior AIX 5.1 and 5.2 releases (which are currently off support) and the AIX 5.3 and 6.1 releases that are still supported by Big Blue.

One interesting thing about the future AIX 7 is that it has a tweaked version of IBM's Workload Partitions (WPARs for short, in IBMspeak) that will allow for AIX 5.2 to run inside the partitions. WPARs are akin to virtual private server partitions like Solaris containers and BSD jails, which have a single operating system kernel and file system that look like multiple operating systems, complete with their own security and tuning, for applications to be isolated in.

WPARs are distinct from logical partitions, or LPARs, implemented by the PowerVM hypervisor, which abstracts the Power iron and allows full AIX, i, or Linux operating systems - with their own kernels and file systems - to run side by side and in a more fully isolated fashion. With AIX 7, customers can take a logical partition running AIX 5.2 and restore it onto an AIX WPAR; this is useful because IBM's live migration in the AIX environment only works on WPARs, not LPARs.

During the beta, IBM is enabling this AIX 5.2 LPAR to WPAR migration to be tested on earlier Power systems, but when AIX 7 does go into production later this year - perhaps in September or October, according to the latest roadmaps from IBM, but really dependent on how the beta goes - this capability will only be enabled on Power7-based machines running AIX 7.

AIX 7 will also take full advantage of all the power management and virtualization features in Power7 systems, but given the relatively few Power7 machines in the field, IBM is not expecting this code to get the same number of eyeballs on it as other AIX 7 features.

Another WPAR enhancement is to allow Fibre Channel adapters to be pegged directly to and be owned by a specific WPAR, which IBM says helps simplify the management of storage on AIX systems that have been virtualized. There is some complaining in the AIX and i customer bases about the AIX Virtual I/O Server that is used to virtualize storage and networking for LPARs running on the PowerVM hypervisor, and presumably letting WPARs own their own I/O not only simplifies configuration, but boosts performance.

IBM also says that AIX 7 will come with built-in high availability clustering for AIX-based systems, but did not elaborate. IBM sells PowerHA SystemMirror clustering software for AIX boxes, formerly known as HACMP and which has been available since 1991.

PowerHA SystemMirror allows up to 32 AIX boxes to be clustered together with shared storage, allowing boxes to back each other up in the event of a crash. It could be that IBM is going to bundle the basic PowerHA clustering software in AIX Enterprise Edition, its high-end variant of AIX with all the bells and whistles.

Other AIX 7 enhancements include domain support in the role-based access control security modules of the operating system, which will help hosting companies with multiple tenants to restrict access to volume groups, file systems, and devices across multiple domains. AIX thin servers (which are diskless and dataless AIX images booted from storage over NFS) will be enhanced to support NFS v4 and IPv6.

IBM will also be tweaking the EtherChannel Ethernet link aggregation feature of its TCP/IP stack (used in conjunction with Catalyst switches from Cisco systems) to support some new features of the IEEE 802.3ad standard.

With the AIX 6.1 beta program, which was launched in July 2007 concurrently with the first rollouts of machines based on the dual-core Power6 processors, over 1,000 companies participated in the beta program, says Kruemcke. IBM had never done a beta program before, and didn't know exactly what to expect, but these numbers were larger than Big Blue anticipated.

Even if they pale compared to the number of companies that participate in Windows or Linux betas, all Unix shops, like mainframe and proprietary midrange shops, are extremely conservative and don't usually have a lot of fallow RISC, Itanium, or proprietary iron laying around, given its high cost.

But independent software vendors who peddle AIX products do have iron to build and test their code, and they want to get their applications up to snuff on the new release. About 30 per cent of the companies that tested AIX 6.1 three years ago were ISVs who, for whatever reason, did not go through the normal channels to gain access to the impending Unix release to get started on porting and testing their code.

The net effect of this, says Kruemcke, is that ISVs were primed for the actual AIX 6.1 release, and many more applications were ready in the wake of the delivery of the operating system than IBM would have otherwise been able to count on. It is reasonable that the AIX 7 beta will get ISVs moving again.

Some users are also keen on moving ahead, says Kruemcke. "A large number of customers are on AIX 5.3, and many of them are looking very seriously about jumping straight to AIX 7."

AIX 6.1 had two betas, with everyone participating in the first and only a small percentage messing around with the tweaks that IBM did in the second beta. So this time around, IBM is only planning to do one beta for AIX 7. ®