Pros of freebsd-src

• Comprehensive operating system source, including kernel, userland, and utilities
• Longer development history and broader scope than ZFS alone
• Includes additional filesystems and storage technologies beyond ZFS

Cons of freebsd-src

• Larger codebase, potentially more complex to navigate and contribute to
• Slower release cycle compared to ZFS-specific updates
• May include older or FreeBSD-specific ZFS implementations

Code Comparison

ZFS (from openzfs/zfs):

int
zfs_ioc_pool_create(zfs_cmd_t *zc)
{
    char *poolname = zc->zc_name;
    nvlist_t *config = NULL;
    nvlist_t *props = NULL;

FreeBSD src (from freebsd/freebsd-src):

static int
zfs_ioc_pool_create(struct cdev *dev, u_long cmd, caddr_t data, int flag, struct thread *td)
{
    zfs_cmd_t *zc = (void *)data;
    char *poolname = zc->zc_name;
    nvlist_t *config, *props;

Both repositories implement ZFS functionality, but freebsd-src includes it as part of a larger operating system codebase. The code snippets show similar function signatures for pool creation, with minor differences in parameter handling and FreeBSD-specific elements.

Pros of illumos-gate

• Broader scope, encompassing a full operating system
• Includes additional features beyond ZFS, such as networking and device drivers
• Maintains compatibility with legacy Solaris applications

Cons of illumos-gate

• Larger codebase, potentially more complex to navigate and contribute to
• Less focused on ZFS-specific improvements and optimizations
• May have slower release cycles due to its comprehensive nature

Code Comparison

illumos-gate (ZFS implementation):

void
zfs_log_history(zilog_t *zilog, const char *intent, const char *readonly,
    const char *history_str)
{
    char *buf;
    size_t len;

zfs:

void
zfs_log_history(objset_t *os, const char *intent, const char *readonly,
    const char *history_str)
{
    char *buf;
    size_t len;

The code snippets show similar function signatures, with illumos-gate using zilog_t *zilog and zfs using objset_t *os as the first parameter. This reflects the different contexts in which ZFS is implemented within each project.

Pros of darwin-xnu

• Tightly integrated with Apple's ecosystem, optimized for macOS and iOS
• Includes advanced security features like System Integrity Protection (SIP)
• Supports Apple-specific hardware and drivers out of the box

Cons of darwin-xnu

• Closed-source components limit customization and third-party contributions
• Less portable across different hardware platforms
• Smaller community and ecosystem compared to ZFS

Code Comparison

darwin-xnu (memory management):

kern_return_t
vm_map_enter(
    vm_map_t                map,
    vm_map_offset_t         *address,
    vm_map_size_t           size,
    vm_map_offset_t         mask,
    int                     flags,
    vm_map_kernel_flags_t   vmk_flags,
    vm_tag_t                tag,
    vm_object_t             object,
    vm_object_offset_t      offset,
    boolean_t               needs_copy,
    vm_prot_t               cur_protection,
    vm_prot_t               max_protection,
    vm_inherit_t            inheritance)

ZFS (dataset management):

int
dsl_dataset_hold(const char *name, void *tag, dsl_dataset_t **dsp)
{
    dsl_pool_t *dp;
    dsl_dataset_t *ds;
    int error;

    error = dsl_pool_hold(name, tag, &dp);
    if (error != 0)
        return (error);

Both projects are complex operating system components, but darwin-xnu focuses on the macOS/iOS kernel, while ZFS is a cross-platform file system and volume manager. darwin-xnu offers tight integration with Apple's ecosystem, while ZFS provides advanced data management features and broader platform support.

Pros of WSL2-Linux-Kernel

• Provides a full Linux kernel experience within Windows
• Enables seamless integration between Windows and Linux environments
• Regularly updated to align with the latest Linux kernel releases

Cons of WSL2-Linux-Kernel

• Limited to Windows systems, not usable on other platforms
• Requires Windows 10 version 2004 or higher
• May have performance overhead compared to native Linux installations

Code Comparison

WSL2-Linux-Kernel:

static int wsl_init(void)
{
    pr_info("Initializing WSL2 Linux Kernel\n");
    return 0;
}
module_init(wsl_init);

ZFS:

static int zfs_init(void)
{
    printk(KERN_NOTICE "ZFS: Loaded module v%s-%s%s\n",
        ZFS_META_VERSION, ZFS_META_RELEASE, ZFS_DEBUG_STR);
    return 0;
}

Key Differences

• WSL2-Linux-Kernel focuses on Windows-Linux integration, while ZFS is a file system and volume manager
• ZFS is platform-agnostic and can be used on various operating systems
• WSL2-Linux-Kernel is tailored for Windows users, whereas ZFS caters to a broader audience of system administrators and developers
• ZFS provides advanced data management features, while WSL2-Linux-Kernel aims to provide a Linux environment within Windows