Running Linux, 5th Edition - Matthias Kalle Dalheimer [482]
Running concurrently on the same computer using an emulator or virtual machine
When Windows and Linux are running on separate hardware, and the systems are not networked, a floppy disk or CD (either CD-R or CD-RW) can be written on one system and read on the other. Both Windows and Linux have the capability to read and write CDs in industry-standard, ISO 9660 format. The cdrecord program, which runs on Linux and other Unix flavors, can create CDs using Microsoft's Joliet extensions to the ISO 9660 standard, making Windows feel right at home with the disk format.
A more cost-effective approach is to install both Windows and Linux on the same computer, each in its own disk partition. At boot time, the user is given the choice of which operating system to run. "Booting the System," in Chapter 17, tells you how to configure a multiboot system. You can then mount your Windows partition directly onto the Linux filesystem and access the Windows files in a manner similar to regular Unix files.
For networked computers, the most outstanding tool for getting Linux and Windows to cooperate is Samba, an open source software suite that lets you access Unix files and printers from Windows. Linux servers running Samba can—depending on the circumstances—serve Windows computers even faster than Windows servers can! In addition, Samba has proven to be very stable and reliable.
The Samba package also includes programs that work with the smbfs filesystem supported by Linux, which allows directories shared by Windows to be mounted onto the Linux filesystem. We discuss the smbfs filesystem and Samba in enough depth to help you mount shared directories and get a basic, functional server running.
Emulators or virtual computers are forms of software that let you run Windows applications directly under Linux, or even run Windows itself. Wine is an open source project with the goal of directly supporting Windows applications without needing to install Windows. Another approach is used by the commercial VMware application, which is able to concurrently run a number of installations of Windows, Linux, FreeBSD, or some other operating systems. When running Windows under VMware, data is shared with the Linux host using the Samba tools.
Finally, remote desktop applications let users on one system log in to other systems and run applications there, or even control the remote systems.
You should be a little skeptical of some claims of compatibility. You might find, for example, that you need twice the disk storage in order to support two operating systems and their associated files and applications programs, plus file conversion and graphic-format conversion tools, and so on. You may find that hardware tuned for one OS won't be tuned for the other, or that even when you've installed and correctly configured all the necessary software, small compatibility issues remain.
Sharing Partitions
As we've explained in the section "Mounting Filesystems" in Chapter 10, partitions on local hard disks are accessed by mounting them onto a directory in the Linux filesystem. To be able to read and write to a specific filesystem, the Linux kernel needs to have support for it.
Filesystems and Mounting
Linux has filesystem drivers that can read and write files on the traditional FAT filesystem and the newer VFAT filesystem, which was introduced with Windows 95 and supports long filenames. It also can read and (with some caveats) write to the NTFS filesystem of Windows NT/2000/XP.
In "Building a New Kernel" in Chapter 18, you learned how to build your own kernel. In order to be able to access DOS (used by MS-DOS and Windows 3.x) and VFAT (used by Windows 95/98/ME) partitions, you need to enable DOS FAT fs support in the File systems section during kernel configuration. After you say yes to that option, you can choose MSDOS fs support and VFAT (Windows-95) fs support. The first lets you mount FAT partitions, and the second lets you mount FAT32 partitions.
If you want to access files on a Windows NT partition that carries an NTFS filesystem,