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Comment Re:As Always (Score 1) 81

There's always Ansible; the remote agent is a SSH server. Communication model is push only. Configuration files are YAML.

There are a dozen different configuration management tools on the market right now. There is almost certainly an option that fits your needs.

Comment Re:NIST definition - Cloud computing (Score 2) 118

It doesn't really need 1.5 pages of description.

Cloud computing is a strong abstraction layer between the physical machine and the logical machine. It's very similar in concept to memory virtualization - each process is given it's own address space, and really doesn't understand or care how that address space maps to physical memory. In a cloud computing environment, you request a new machine, and the cloud computing infrastructure automatically allocates a machine based on your requirements. The abstraction layer allows your physical hardware to be treated as a pool of resources, that can be expanded, repaired, or replaced without much concern about the impact to the logical machines it supports.

Cloud computing doesn't necessarily require virtualization either; physical computers can be provisioned using cloud infrastructure; https://wiki.openstack.org/wiki/Baremetal

Comment Re:Did it really work? (Score 1) 332

I need to offer you credit; you are right. The issue isn't really PAE, it's how the kernel manages memory on 32 bit x86 architectures with more than 1GB of memory installed. PAE simply exacerbates the problem. Here's an explanation of the complaint:

On ia_32 systems, the kernel splits memory into 3 zones; DMA, NORMAL, and HIGHMEM.

ZONE_DMA is the first 16MB of memory, and is generally avoided unless needed (due to lack of available higher memory, or for DMA mappings.) The kernel tries to reserve this address range for devices that use DMA mapping.

ZONE_NORMAL is an address space that is directly accessible to the kernel, and extends from 16MB to 896MB. Kernel data structures are stored in this space, including the kernel page tables. Memory mappings start to consume a lot of memory in ZONE_NORMAL, and thus PAE on ia_32 with a lot of installed memory can cause out of memory issues, even when there is a lot of available physical memory. User data can be allocated into ZONE_NORMAL, but is preferred to be placed in ZONE_HIGHMEM to free ZONE_NORMAL for kernel data structures.

ZONE_HIGHMEM is memory above the 896MB barrier. This address range is not directly accessible to the kernel. In order for the kernel to access anything in this zone, a temporary map must be made into ZONE_NORMAL. These mappings consume pages of ZONE_NORMAL, and suffer a performance hit. User space processes can access these pages directly (handled by the virtual memory manager system, of course.)

Generally, memory will be allocated to ZONE_HIGHMEM, ZONE_NORMAL, or finally ZONE_DMA in that order of preference.

The x86_64 architecture eliminates the need ZONE_HIGHMEM. ZONE_NORMAL extends all the way from 16MB to the end of physical memory. This approach simplifies memory management, improves performance, and is generally more flexible.

You're correct that there was a major issue with my original post... My memory of the kernel architecture had garbled HIGHMEM with PAE, and I was thinking that PAE required mapping pages above 4GB into lower memory. This would of course cause a huge performance penalty for any process consuming memory above 4GB. I deserve downmods for the technical inaccuracy.

Here's a very brief summary of the problems with HIGHMEM:
http://linux-mm.org/HighMemory

Here's a bunch of links used to refresh my memory:

http://www.makelinux.net/ldd3/chp-15-sect-1
https://www.kernel.org/doc/gorman/html/understand/understand005.html
http://unix.stackexchange.com/questions/5143/zone-normal-and-its-association-with-kernel-user-pages

Comment Re:Did it really work? (Score 1) 332

Yes, this is a bit of an oversight on my part. I really should have been discussing the way PAE is implemented on ia32 processors. I had a little bit of difficulty finding information about it online, I'll have to consult my architecture books at home, and will expand on the original post. Here's a bit of the info I could find about PAE weirdness on IA32.

https://www.kernel.org/doc/gorman/html/understand/understand005.html#sec: High Memory

The key quote:

PAE allows a processor to address up to 64GiB in theory but, in practice, processes in Linux still cannot access that much RAM as the virtual address space is still only 4GiB. This has led to some disappointment from users who have tried to malloc() all their RAM with one process.

Secondly, PAE does not allow the kernel itself to have this much RAM available. The struct page used to describe each page frame still requires 44 bytes and this uses kernel virtual address space in ZONE_NORMAL. That means that to describe 1GiB of memory, approximately 11MiB of kernel memory is required. Thus, with 16GiB, 176MiB of memory is consumed, putting significant pressure on ZONE_NORMAL. This does not sound too bad until other structures are taken into account which use ZONE_NORMAL. Even very small structures such as Page Table Entries (PTEs) require about 16MiB in the worst case. This makes 16GiB about the practical limit for available physical memory Linux on an x86. If more memory needs to be accessed, the advice given is simple and straightforward, buy a 64 bit machine.

Comment Re:Did it really work? (Score 4, Interesting) 332

I think if you understand how truly horrifying PAE is, you would have no doubt at all that 64 bit platforms were the way to go. There's a lot of memory management cruft in the Linux kernel that x86_64 eliminates.

x86_64 also slipped in a few much needed enhancements to the ia32 architecture, including some extra general purpose registers.

http://en.wikipedia.org/wiki/X86-64

Comment What seasons 5&6 wasn't character development (Score 2) 390

I don't really think the newer seasons developed the characters... I think they tended to continue the Federalization that had started to set in through season 4 of the original run.

IMO, establishing facts about a character, revealing the back-story of a character, or establishing a relationship between characters is not the same as character development... This is something that the later writers need to understand.

Here's an example of strong character development:

In parasites lost, Fry becomes something of an ideal man thanks to the efforts of a worm he picks up from a truck-stop egg salad sandwich. His strength, intelligence, and artistic ability make him attractive to Lela. For one of the first times in the Series, Fry and Leela become close romantically. But ultimately, Fry gives up all of his new-found strength, because Fry wanted the relationship to be based on who he was in and of himself, rather than how he was perceived by Leela. Fry's character is further developed when he starts to practice the Holophoner in order to become the person Leela respected.

This episode was a huge character defining moment for Fry. This episode did not have a significant impact on Futurama continuity. What it did was to truly help us understand fry as a person in a way that Lars never really could. It developed Fry in a way that his season 5 & 6 relationship with Leela didn't.

I think Fry somewhat devolved as a character during the comedy central run of Futurama. His sincerity is still there, but it seems like a part of his core personality. His stupidity becomes a much more predominant characteristic. He started to feel like a young, orange haired Homer Simpson.

For what it's worth, I think The Late Phillip J. Fry and the Prisoner of Benda were gems from the later seasons. There was some good stuff in seasons 5 & 6, and some bad stuff in Seasons 1-4, but on average I was kind of disappointed by seasons 5&6. I haven't been following Futurama nearly as closely as I once did.

"In the year twenty-five twenty-five twenty-five
The backwards time machine still won't have arrived
In all the world, there's only one technology
A rusty sword for practicing proctology"

Comment Teathering is NOT unlimited (Score 2) 404

I am currently a T-mobile customer, and had a chance to look over the plans. Very excited by this new approach, and hope other providers follow suit.

It's important to note however that tethering (Smartphone Mobile HotSpot, or SMH) is not unlimited, even with the unlimited data plans. The unlimited data plan included 500MB of tethered data, and you can buy more (apparently for $10 per 2GB, but not confirmed.) If you're primarily interested in tethered data, it might make sense to buy the 2.5GB plan, which costs $10 less, and includes 2.5GB of tethered data.

Unfortunately, it looks like T-mobile may be eliminating some of it's other low cost plans with this move. My current plan is $30/mo for more 1500 talk/text minutes, and 30MB of data. 30MB is enough to check a map when I need it, and I can use wifi for my typical data use.

If you have concerns about T-Mobile's coverage, you can supplement it by purchasing an inexpensive daily use phone from Verizon. Pay $2/day when you're traveling outside a T-Mobile coverage zone.

Comment Re:my whole class was taught to program in high sc (Score 1) 265

That's fine. The purpose of programs at that level shouldn't be to produce a class full of programmers, but instead to help point students with the aptitude to program towards it as a possible career path.

I'm in the IT field because of a 3 hour computer repair class I took as a kid. I never expected to enjoy it or be good at it - it's just something I did. Turned out to be the right decision for me.

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