After seven months of development, the release of DragonFlyBSD 6.2 has been published, an operating system with a hybrid kernel created in 2003 for the purpose of an alternative development of the FreeBSD 4.x branch. Among the features of DragonFly BSD, we can highlight the distributed versioned file system HAMMER, support for loading βvirtualβ system kernels as user processes, the ability to cache data and FS metadata on SSD drives, context-sensitive variant symbolic links, the ability to freeze processes while saving their state on disk, hybrid kernel using lightweight threads (LWKT).
Major improvements added in DragonFlyBSD 6.2:
- The NVMM hypervisor has been transferred from NetBSD, supporting hardware virtualization mechanisms SVM for AMD CPUs and VMX for Intel CPUs. In NVMM, only the minimum necessary set of bindings around hardware virtualization mechanisms are performed at the kernel level, and all hardware emulation code runs in user space. Tools based on the libnvmm library are used to perform tasks such as creating virtual machines, memory allocation, and VCPU allocation, and the qemu-nvmm package is used to run guest systems.
- Work continued on the HAMMER2 file system, which is notable for such features as separate mounting of snapshots, writable snapshots, directory-level quotas, incremental mirroring, support for various data compression algorithms, multi-master mirroring with data distribution to several hosts. The new release introduces support for the growfs command, which allows you to resize an existing HAMMER2 partition. It includes experimental support for the xdisk component, which allows you to mount HAMMER2 partitions from remote systems.
- The DRM (Direct Rendering Manager) interface components, the TTM video memory manager and the amdgpu driver are synchronized with the Linux kernel 4.19, which made it possible to provide support for AMD chips up to the 3400G APU. The drm/i915 driver for Intel GPUs has been updated, adding support for Whiskey Lake GPUs and resolving the issue with startup crashes. The Radeon driver has been converted to use the TTM video memory manager.
- The poll call provides support for the POLLHUP event returned when the second end of an unnamed pipe or FIFO is closed.
- The kernel has significantly improved memory page handling algorithms, increased efficiency when selecting pages to move to the swap partition, and significantly improved the behavior of resource-intensive applications such as browsers on systems with small amounts of memory.
- Changed maxvnodes calculation to reduce kernel memory consumption, as caching too many vnodes can reduce performance, for example if data blocks are additionally cached at the block device level.
- Support for the BeFS file system has been added to the fstyp utility. Support for the FAT file system has been moved to makefs from FreeBSD. Improved performance of the fsck and fdisk utilities. Fixed bugs in ext2fs and msdosfs code.
- Added ioctl SIOCGHWADDR to obtain the hardware address of the network interface.
- ipfw3nat adds NAT support for ICMP packets, implemented through icmp idport reuse.
- The ichsmb driver has added support for Intel ICH SMBus controllers for Cannonlake, Cometlake, Tigerlake and Geminilake chips.
- Generation of initrd files has been switched from using vn to makefs.
- The functions getentropy(), clearenv() and mkdirat() have been added to the libc standard library. Improved compatibility of shm_open() and /var/run/shm implementations with other systems. Added platform-specific __double_t and __float_t types. Encryption-related functions have been returned to libdmsg. Improved pthreads performance.
- In the dsynth utility, designed for local assembly and maintenance of DPort binary repositories, the β-Mβ option and the PKG_COMPRESSION_FORMAT variable have been added. Provided support for the pkg 1.17 package manager and the second version of the pkg metadata.
- The OpenPAM Tabebuia PAM library, passwdqc 2.0.2 password checking utility, mandoc 1.14.6, OpenSSH 8.8p1, dhcpcd 9.4.1 and file 5.40 packages are imported into the package.
- Fixed a locally exploitable vulnerability in the kernel that could allow a user to escalate their privileges on the system (CVE not reported).
- The ndis driver, which allowed the use of binary NDIS drivers from Windows, has been removed.
- Support for the a.out executable file format has been discontinued.
Source: opennet.ru