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Re: bgb, references for mailing lists?...


From: cr88192 sydney
Subject: Re: bgb, references for mailing lists?...
Date: Tue, 12 Mar 2002 06:03:31 +0000

err, bfd... I am not terribly knowlegable about it and I am not sure how well it would for for things other than object-files.

for the fs I was imagining using an object mesh like design. before I had planned on an "semantic" fs model (and that is about what I had coded). I had come to realize that that model would not work well for what I was imagining, so I came up with a new one. I had figured: why not rip off what I can from scheme? some details do not so cleanly map over but I can work them out.

misc: a gc was supprisingly easy to write, though mine was based on my mm which used the first fit algorithm. I have been planning on writing an alternate allocator for small stuff (a cell based or buddy allocator), as my allocator has an overhead of 32 bytes/object. I had imagined a cell or buddy allocator would be inefficient when dealing with larger objects. sorry I don't know how the guile gc/allocator works... I had imagined 2 allocators would be complicated though. I had written part of a cells allocator, it works by allocating objects and mapping cells and a bitmap into them, my cell allocator does not use best fit, as I imagine that most objects are only only a few cells. each cell objects has an overhead of 12 bytes (4 bytes header, 4 bytes backlink, 4 bytes block-head reference). the cell index is computed from the address (I could do without the block-head reference, but more general code expects it).
I do crappy at this.

I doubt I can use guile in my kernel, as I imagine it might be a lot of work to rewrite to work in it. I might have to write my own... actually this almost take priority over new fs, as they would need to be effectivly interconnected.

my current fs stuff is a cheap vfs rip... with support for: fat (crappy, hackish, buggy); devfs (lists known devices); and ramfs (ram based fs, not persistent, used as root). it is buggy, and it is heirarchical (as when first writting it I didn't have many other ideas, except relational and I didn't want to try to make my old dbms code work as a fs). the "semantic" model in my oppinion is just a tweaked out heirarchical model. I imagine an object mesh could emulate the other models... my early fs spec involved using vectors to emulate b-trees. I will not go into the details.

I hope I don't overpromote this...


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