'ReadyBoost' for KNOS?

[pharrisire]

Since it seems like neither one of these 8G Kingston sticks are going to
work for KNOS(32 or 64) , is there a BSD/KNOS equivalent to Windows
'ReadyBoost' so that they could give the Lenovo the benefit of having
18G ram instead of the installed 2G it has internally? Three of the four
usb slots are unused so there is plenty of room for them to be
plugged in full time...

[Kevin McAleavey]

Just heard back from the BSD folks, turns out that Kingston's sticks are FULL of "quirks" and the "DataTraveler 160 1.00" sticks weren't known to them. From what I'm told, they all have an issue with SCSI sense because they're not really SCSI devices, but are organized in rows and columns internally to appear as such. They don't HAVE a "cache" and that's what's causing the problem. Most sticks DO have an internal cache, theirs don't. So there's the problem. I'm going to send you an email separately since they want to have you try something that may result in a fix in their next kernel release.

For your intents there then, they wouldn't work for that anyway since it's those caches that are the secret to Windows' "ReadyBoost" thing. "ReadyBoost" isn't actually intended for USB sticks either, though they can sorta be used for that but they're too slow to be really useful. Microsoft's thing is actually intended for SSD drives which are faster than normal hard drives even when externally connected. ReadyBoost was useful for a short period of time when machines were RAM-limited, drives were slow, and flash was cheap. With RAM so cheap now, it makes much more sense to use RAM instead. Typical flash drives these days have write speeds of only about 5MB/s and read speeds of about 20MB/s. Compare that to your hard drive's 50MB/s read and write and there doesn't seem to be much point. Real-world performance benefits from ReadyBoost are only seen on heavily memory-constrained systems, and 2GB is perfectly adequate.

That all said, BSD doesn't support "ReadyBoost" itself, it has other means to accomplish the same thing in two superior ways. ReadyBoost is the same as "swap" except that in Windows, that swap space is pushed off your main hard disk onto other drive space. So the existing swap space that's already on your bootable KNOS disk could be moved to one of those sticks, but the superior memory management in KNOS compared to other OS' would only end up slowing things down drastically. Swap is SLOW on BSD. It's intended only to push things out that haven't done anything in a while but are still loaded. The more efficient way would be to close programs you're not using because KNOS' memory-only file system is much faster than any media can be. Our memory management already in the KNOS you have is designed to fast cache frequently used data and recycles memory much faster than any other OS. As a plus, since needed data is already precached (that's why program loads are slow because we recycle memory so quickly) performance is actually faster.

Now in a CUSTOM build of KNOS, if that was a requirement, the ZFS filesystem already exists and works very nicely. But that would require a custom build since that's not the way we normally do things in our retail version as we need very tight specification of what is connected, and it has to be there in the machine at all times to work properly. If an institutional customer is putting KNOS directly onto the hard drives of their machines, then we can bring that all together nicely. It's much harder to configure ZFS for just one individual machine, and the retail version you have uses regular UFS which has no special requirements. But the answer is yes, it CAN be done, but not in the retail version. It would have to be built "special."