Even though I usually don’t work at the weekend, I had to, since I didn’t manage to work 8 hours on friday.
Unfortunately, I still haven’t got SMP to work yet. I’ve investigated the issue, and came to the simple conclusion that the APIC interrupts doesn’t reach their goal (it just took me some time to get there, and exlude all other possible faults). I can trigger such an interrupt manually, so the second CPU is setup correctly, but its APIC doesn’t seem to be.
It took a bit longer to get the dual machine up and running again - it has two 500 MHz PIIIs and the hard drive is a bit older as well, so it took about two hours to update the source repository and get it compiled.
While waiting for the machine to complete its task, I had the time to look into some other known issues of our code, and clean the signaling code a bit.
I’m done implementing sub transactions for now - I haven’t yet tested detaching sub transactions, but everything seems to work fine. Time will tell :-)
A complete Tracker build now dropped from 13.5 minutes to 5.4 minutes - that’s great, but BeOS R5 does the same job on this machine in around 2.5 minutes, so even while this is an improvement, we still have a long road ahead of us. I can only guess where we lose those 3 minutes for now, but I am sure we’ll find out well before R1.
A small update to the BFS incompatibility: I’ve now ported the original logging structure to the R5 version of BFS as well, so that the tools like bfs_shell can now successfully mount “dirty” volumes, too. I also found another bug in Be’s implementation, and needed to cut down the log entry array by one to make it work with larger transactions.
Now I am working on implementing sub transactions. If you have tried out Haiku and compiled some stuff or just redirected some shell output to a file, you undoubtedly are aware that this takes ages on the current system.
Turns out BFS logging code is not that intelligent - it uses block_runs in the log area, but it doesn’t make use of them. In other words: it only accepts block_runs with length 1 - which effectively kills the whole idea of using them. It’s now as space consuming as the single block number arrays I had before, but doesn’t share the binary search capability we had earlier.
While our code now could use block_runs how they should be used, I have disabled joining separate block_runs to make our BFS fully compatible to Be’s in this regard.
This morning, I went through analyzing the BFS log area structure. Turns out it’s very different from what I did for our BFS.
Our current log structure looks like this:
block 1 - n:
uint64 number of blocks
off_t array of block numbers
block n+1 - m:
real block data
While the one from BFS looks like this:
uint32 number of runs
uint32 max. number of runs
First of all, I successfully booted Haiku from CD-ROM from several machines today. It took a bit longer than I thought, as no emulator that I have access to seems to support multi-session CDs, and not every BIOS I have works by the book. The boot device selection is still very simplistic, so it might not end up booting completely from CD if you just inserted it, and didn’t choose “Boot from CD-ROM” in the boot loader - but you’ll have to bear with that currently.
Everything is in place now, and the boot loader is even passing all information to the kernel to be able to boot from a CD. It’s not yet working though, as the VFS is only evaluating the partition offset of the boot volume, and nothing more.
It’s probably only a tiny bit left, so I try to finish it tomorrow - in my spare time, as I usually don’t work during the weekend :-)
Since Ingo and I started working on CD booting at BeGeistert, we have (or rather, he has) written a TAR file system for the boot loader.
When your IBM compatible computer boots, the BIOS emulates a boot floppy for a CD-ROM instead of giving you access to the disk directly. In order to access the whole disk, we need a CD-ROM driver - and therefore, we also need the kernel to execute the driver.
This blog is supposed to accompany my Haiku development efforts while being employed by the non-profit organisation behind Haiku , Haiku Inc.
Thanks to the donations you made to Haiku Inc., I will work full time until the end of november - that means 8 hours a day, 5 days a week. I’m not getting rich by doing this, but it should be enough to pay my bills. I don’t even get more money if you would donate more - it would just make such an event more likely to happen again.