This thread is no longer about Clojure - please take it elsewhere. Thanks,
Rich On Aug 30, 2011, at 8:54 PM, Ken Wesson wrote: > On Tue, Aug 30, 2011 at 2:19 PM, Phil Hagelberg <p...@hagelb.org> wrote: >> On Tue, Aug 30, 2011 at 10:10 AM, Ken Wesson <kwess...@gmail.com> wrote: >>>> VirtualBox is free: http://www.virtualbox.org/ >>> >>> Emulators? I hadn't considered those [...] >>> >>> I'd think it especially likely that if there's a free one, there're a >>> lot of software that won't quite work the same as on a separate PC, >>> and will be outright broken in some cases. >> >> Virtualbox is not an emulator; it's a virtualization tool. > > Same difference. Just because the processor hardware doesn't need to > be emulated doesn't make it not an emulator. > >> On modern hardware (core 2+) it's capable of running at full CPU >> speed with a minor I/O perf penalty. On our team we develop almost >> exclusively in it; there are no emulation quirks. > > There will be filesystem emulation quirks, though probably not as bad > as the Cygwin/Windows impedance mismatch another thread here recently > discussed. This might extend into other hardware-I/O-intensive areas > of program operation too. Have you ever tried to run a complex Windows > program, especially a recent game, in Wine? Well, Cygwin is like doing > that with the Linux/Windows roles reversed. VirtualBox will make the > interface point closer to the metal than Cygwin, with some big volume > image file in the host FS emulating a hard drive rather than just > using the host FS as the Linux FS. Anything that depends on low-level > behavior of a real disk drive will have problems, and that likely > includes fsck, which may run at bootup under some circumstances (such > as if the hosted Linux "thinks" it wasn't shut down normally last > session -- and if VirtualBox crashes, which, being Windows software, > eventually it will, that's likely to happen; also if there's a garden > variety power outage). Database software (for heavyweight enough DBs) > also tends to play with disk drives at a low level, for instance by > implementing a B-tree right on the platters in a separate partition in > lieu of using a file or files in the operating system's FS. The latter > could be worked around, by hosting the database from Windows or by > using a spare external disk drive (which might not have been a viable > boot device, preventing simply installing Linux to it and obviating > the need for VirtualBox). > > MacOS, of course, probably has DRM that examines the hardware to make > sure it's running on a genuine Mac. If the emulator doesn't fool it > successfully it won't run, and if it does it could be treated in the > US as a DMCA violation (stupidly enough this is true even if there's > no actual copyright infringement, i.e. the copy of MacOS is not > pirated). I wouldn't be surprised if Apple does funny, proprietary > things to the boot drives in its hardware that the DRM will check for > and that VirtualBox's emulation of a hard drive probably won't pass > this test. > >> If you are stuck on Windows without the option of adding an OS to your >> machine, Virtualbox is a great way to get a nice isolated development >> environment going. It also has the benefits of being easier to >> automate, snapshot, and not avoid interfering with the operation of >> your host. > > As long as whatever differences do exist, and there will be some, > don't trip you up in some manner. A better use might be to install > Windows, a web browser, and little else to it, take a snapshot, and > use it for surfing, backing up downloaded files and your bookmarks now > and again; if you get infected, or want to be really sure of clearing > all history, including Flash cookies and any other stuff plugins might > squirrel away outside the HTTP cookie mechanism for privacy reasons, > restoring a backed up image over top will reset it. Another use would > be to run Linux, a server, and ancillary tools, snapshot it, and turn > it on; it's a bit more work to get the server back up after any > shutdown, but on the other hand if you get hacked the attackers > probably can't find their way out of the virtual box and may not even > realize they're in one. The stuff in the host is probably safe. > > Antivirus companies use them now, with old unpatched Windows versions > running in them, to test suspicious files people send them. They > probably also surf pr0n sites unprotected from wide-open Win98 boxes > to see what's out there. Then halt the emulator and dissect the drive > image file to see exactly what the infection(s) did, without the > infection(s) interfering even if they have rootkit-like qualities. > > But for development, I'd be worried that the differences (even in > performance characteristics) from a normal box could interfere in > unforeseen ways. In the worst case, you could end up developing > software that works only in VirtualBox-hosted systems. :) > > -- > Protege: What is this seething mass of parentheses?! > Master: Your father's Lisp REPL. This is the language of a true > hacker. Not as clumsy or random as C++; a language for a more > civilized age. > > -- > You received this message because you are subscribed to the Google > Groups "Clojure" group. > To post to this group, send email to clojure@googlegroups.com > Note that posts from new members are moderated - please be patient with your > first post. > To unsubscribe from this group, send email to > clojure+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/clojure?hl=en -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
