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35-511: Initially the company produced PMD 85 compatible machines aimed at schools, then switching to the home market with ZX Spectrum clones. Didaktik's glory diminished with the falling price of the 16-bit computers, such as the Atari and Amiga , around the middle of the 1990s until it was finally steam-rolled by the PC soon after. The production of Didaktik computers stopped in the year 1994. Didaktik Alfa

70-586: A 8255 chip was added, providing centronics plotter and printer connections and a Kempston joystick port. The case was similar to that of the ZX Spectrum+, a grey or black box in A5 size, with a flat plastic keyboard and connectors mounted on the rear side. The Gama uses a standard ULA chip made by Ferranti. All games developed for the ZX Spectrum 48K were generally compatible with this computer. An audio cassette

105-493: A feature known as Safe Sleep saves the contents of volatile memory to the system hard disk each time the Mac enters Sleep mode. The Mac can instantaneously wake from sleep mode if power to the RAM has not been lost. However, if the power supply was interrupted, such as when removing batteries without an AC power connection, the Mac would wake from Safe Sleep instead, restoring memory contents from

140-415: A general energy saving measure and allows for replacement of a removable battery quickly. Google and Apple mobile hardware ( Android , Chromebooks , iOS ) do not support hibernation. Apple hardware using macOS calls hibernation Safe Sleep. A real-time clock alarm can be scheduled to wake the machine after hibernation. Many systems support a low-power sleep mode in which the processing functions of

175-490: A printer interface. Unlike the previous version of Didaktik, these connectors were proprietary, with no compatible peripherals available in Czechoslovakia . Thus, users were forced to develop and produce various homemade interfaces to satisfy their needs. A 5.25-inch floppy disk drive, called D40, was introduced in 1992 and featured a "Snapshot" (see hibernation ) button that stored the current memory contents on diskette. It

210-460: A type of hibernation (Fast Startup) by default when shutting down. After hibernating, the hardware is powered down like a regular shutdown. The system can have a total loss of power for an indefinite length of time and then resume to the original state. Hibernation is mostly used in laptops , which have limited battery power available. It can be set to happen automatically on a low battery alarm. Most desktops also support hibernation, mainly as

245-439: Is a means of avoiding the burden of saving unsaved data before shutting down and restoring all running programs and re-opening documents and browser tabs. Both hibernation and sleep preserve memory fragmentation and atrophy that lead to mobile devices working poorer the longer they run without a full reboot. This is why many experts recommend a frequent shut down or reboot of electronic devices. The first working retail hibernation

280-593: Is an 8-bit personal computer produced since 1985 by the companies Tesla Piešťany and Tesla Bratislava in the former Czechoslovakia . The production was local, due to a lack of foreign currency for purchasing systems from the West . They were deployed en masse in schools throughout Slovakia , while the IQ 151 performed a similar role in the Czech part of the country. The first Czechoslovak video games were created on

315-628: Is as big as the total RAM installed. Windows Me , the last release in the Windows 9x family, also supports OS-controlled hibernation like Windows 2000 and requires disk space equal to that of the computer's RAM. Windows XP further improved support for hibernation. Hibernation and resumption are much faster as memory pages are compressed using an improved algorithm; compression is overlapped with disk writes, unused memory pages are freed and DMA transfers are used during I/O. hiberfil.sys contains further information including processor state. This file

350-494: Is defined as sleeping mode S4 in the ACPI specification. On Windows computers, hibernation is available only if all hardware and device drivers are ACPI and plug-and-play –compliant. This allows some desktop computers to hibernate quickly to SSD in the event of a power failure and power supplied to even a lightweight or aging UPS . Hibernation can be invoked from the Start menu or

385-436: Is installed because of performance issues associated with saving such a large pool of data from RAM to disk. This would later be resolved by Windows 7 and Windows Server 2008 R2 . Windows Vista introduced a hybrid sleep feature, which saves the contents of memory to hard disk but instead of powering down, enters sleep mode. If the power is lost, the computer can resume as if hibernated. Windows 7 introduced compression to

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420-694: Is often underused in business environments as it is difficult to enable it on a large network of computers without resorting to third-party PC power management software. This omission by Microsoft has been criticized as having led to a huge waste in energy. It is possible to disable hibernation and delete hiberfil.sys . Third-party PC power management software offers features beyond those present in Windows. Most products offer Active Directory integration and per-user or per-machine settings with more advanced power plans, scheduled power plans, anti-insomnia features and enterprise power usage reporting. On Macs,

455-455: The Shut Down option, it hibernates the computer, but closes all programs and logs out the user session before hibernating. According to Microsoft, a regular hibernation includes more data in memory pages which takes longer to be written to disk. In comparison, when the user session is closed, the hibernation data is much smaller and therefore takes less time to write to disk and resume. Users have

490-517: The Velvet Revolution of 1989 the computer market opened. The PMD 85 was not competitive in terms of quality or features to foreign machines and production stopped. The PMD 85-2 was an inspiration for the MAŤO personal computer, released in 1989 as a self-assembly kit . It had different hardware and very limited compatibility - BASIC , memory structure and I/O were almost similar, but the tape format

525-550: The CPU and display, which is almost instantaneous. On the other hand, a system in sleep mode still consumes power to keep the data in the RAM, and thus cannot last indefinitely, as hibernation can. Detaching power from a system in sleep mode results in data loss, while cutting the power of a system in hibernation has no risk; the hibernated system can resume when and if the power is restored. Both shut down and hibernated systems may consume standby power unless they are unplugged. Hibernation

560-476: The FAT32 file system, making hibernation problematic and unreliable. Windows 2000 is the first Windows to support hibernation at the operating system level (OS-controlled ACPI S4 sleep state) without special drivers from the hardware manufacturer. A hidden system file named " hiberfil.sys " in the root of the boot partition is used to store the contents of RAM when the computer hibernates. In Windows 2000, this file

595-604: The PMD 85 (other platforms were ZX Spectrum and Atari ). Several variants were developed ( PMD 85-0 , PMD 85 , PMD 85-2 , PMD 85-2A , PMD 85-3 ), with slightly different specifications and compatibility. In 1986 compatible machines were introduced by Didaktik : Didaktik Alfa 1 (a PMD 85-1 clone) and Didaktik Alfa 2 ( a PMD 85-2 clone). Didaktik Beta was a slightly improved Didaktik Alfa, having almost identical hardware. Didaktik Alfa and Beta were mostly deployed in schools to replace older PMD 85 computers. After

630-452: The command line. Windows 95 supports hibernation through hardware manufacturer-supplied drivers and only if compatible hardware and BIOS are present. Since Windows 95 supports only Advanced Power Management (APM), hibernation is called Suspend-to-Disk. Windows 98 and later support ACPI. However, hibernation often caused problems since most hardware was not fully ACPI 1.0 compliant or did not have WDM drivers. There were also issues with

665-474: The computer saves the contents of its random access memory (RAM) to a hard disk or other non-volatile storage . When the computer is turned on the RAM is restored and the computer is exactly as it was before entering hibernation. Hibernation was first implemented in 1992 and patented by Compaq Computer Corporation in Houston , Texas. Microsoft's Windows 8 , Windows 8.1 , Windows 10 and Windows 11 employ

700-630: The hard drive. Because Safe Sleep's hibernation process occurs during regular Sleep, the Apple menu does not have a "hibernate" option. Safe Sleep capability was added in Mac models starting with the October 2005 PowerBook G4 (Double-Layer SD). Safe Sleep requires Mac OS X v10.4 or higher. Shortly after Apple started supporting Safe Sleep, Mac enthusiasts released a hack to enable this feature for much older Mac computers running Mac OS X v10.4. The classic Mac OS once also supported hibernation, but this feature

735-410: The hibernation file and set the default size to 75% of the total physical memory. Microsoft also recommends that the size be increased using the powercfg.exe tool in some rare workloads where the memory footprint exceeds that amount. It can be set from anywhere between 50% and 100%, although decreasing it is not recommended. Windows 8 also introduces a Fast startup feature. When users select

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770-445: The machine are lowered, using a trickle of power to preserve the contents of RAM and support waking up. Instantaneous resumption is one of the advantages of sleep mode over hibernation. A hibernated system must start up and read data from permanent storage and then transfer that back to RAM, which takes longer and depends on the speed of the permanent storage device, often much slower than RAM. A system in sleep mode only needs to power up

805-491: The midst of disk writes and operations with a math co-processor . It could also be controlled using an optional software GUI or a customized keyboard shortcut. It was tested on DOS, Windows 3.1, Banyan Vines, and Novell Netware. Compaq's hibernation is also noted in an IBM patent from 1993. Early implementations of hibernation used the BIOS as noted above, but modern operating systems usually handle hibernation themselves. Hibernation

840-462: The option of performing a traditional shutdown by holding down the Shift key while clicking Shut Down and it is also possible to shut down a computer in the traditional way by disabling Fast Startup in the system settings. Windows 10 mirrors Windows 8 as noted by Microsoft. Windows 10's hibernation algorithm is solid-state drive optimized. This behavior is carried over to Windows 11 . Hibernation

875-479: The original ZX Spectrum bugs in a more compatible way, and also fixed the memory switching bug. The final and the more compatible model was Gama '89 . The computer was expensive but available on the market and could be purchased in Czechoslovak currency outside specialized Tuzex stores, unlike other foreign home computers. Production of Didaktik Gama computers ceased in 1992. The Didaktik M introduced in 1990,

910-435: Was a slightly improved version of previous Didaktik Alfa, having almost identical hardware. Didaktik Alfa and Beta were mostly deployed in schools to replace older PMD 85 computers. Didaktik Gama was a ZX Spectrum clone with 80 KB RAM divided into two switched 32 KB memory banks and 16 KB of slower RAM containing graphical data for video output, while the size of ROM was 16 KB. A peripheral interface with

945-485: Was cheaper and simple in design than the Gama. The case was more modern, with an ergonomic -like shape and separate arrow keys (however, the keyboard was of poorer quality). Inside there was only 64 KB of total memory (16 KB ROM and 48 KB RAM) which was a disappointment in comparison to the Gama. The computer was considerably redesigned. Instead of the original ULA , a custom circuit from Russian company Angstrem

980-505: Was different. It was intended as a home computer, but never really caught on. The same year ZBA , a company from Brno , introduced the Consul 2717, another PMD 85-2 clone, sold to schools. Production of this machine ended in 1990. Hibernation (computing) Hibernation (also known as suspend to disk , or Safe Sleep on Macintosh computers ) in computing is powering down a computer while retaining its state. When hibernation begins,

1015-579: Was documented by security researcher Matthieu Suiche during Black Hat Briefings 2008 who also provided a computer forensics framework to manage and convert this file into a readable memory dump. The compression feature was later documented by Microsoft as well. Although Windows XP added support for more than 4 gigabytes of memory (through Windows XP 64-bit Edition and Windows XP Professional x64 Edition ), this operating system, as well as Windows Server 2003 , Windows Vista and Windows Server 2008 do not support hibernation when this amount of memory

1050-555: Was dropped by Apple. In the Linux kernel , hibernation is implemented by swsusp which is built into the 2.6 series. An alternative implementation is TuxOnIce which is available as patches for the kernel version 3.4. TuxOnIce provides advantages such as support for symmetric multiprocessing and preemption . Another alternative implementation is uswsusp . All three refer to it as "suspend-to-disk". systemd , if deployed, manages hibernation itself. Sleep mode and hibernation can be combined:

1085-561: Was in 1992 on the Compaq LTE Lite 386 as noted in its sales material. It is made possible in part due to the sleep and protected mode opcodes in the Intel 386 CPU . It was implemented in ROM and worked independently of the operating system with no drivers needed. The LTE would sense low battery and prevented data loss by making use of a hidden partition . It preserved and restored the system in

Didaktik - Misplaced Pages Continue

1120-549: Was produced in 1986, as a "more professional" clone of PMD 85 . It featured 2.048 MHz Intel 8080 CPU, 48  KB RAM , 8 KB ROM with built-in BASIC , good keyboard (compared with PMD 85), monitor video output (but no TV output) with 288×256 resolution and four possible colours. Despite some changes in ROM, it was mostly compatible with PMD 85. Didaktik Alfa 1 was a clone of PMD 85-1, Didaktik Alfa 2 of PMD 85-2. Didaktik Beta

1155-465: Was then possible to later load this memory image and continue the software from its previous state. A 3.5-inch floppy disk drive, called D80, was also introduced later in 1992, simultaneously to the release of the Didaktik Kompakt. The Didaktik Kompakt from 1992 was basically a Didaktik M with a built-in 3.5-inch 720 KB floppy drive and a parallel printer port. PMD 85 The PMD 85

1190-456: Was used as data storage and a TV served as a monitor . It is generally said the Gama was unreachable to buy and there were waiting lists several years long. Didaktik Gama was produced in three variants: the first, Gama '87 , fixed some bugs in the original ZX Spectrum ROM (thus breaking compatibility with some software) and introduced its own bugs effectively inhibiting the use of the second 32 KB memory bank from BASIC. Gama '88 fixed

1225-526: Was used, giving a square screen aspect ratio , instead of a typical 4:3 rectangle. In addition, the whole RAM was implemented by a single set of 64 KB chips, from which only 48 KB were used. There was no difference between fast and slow memory regarding video content. System timings were different to the original ZX Spectrum, which prevented some software from displaying timing dependent visual effects. There were two separated connectors for joysticks and one connector for additional hardware, such as

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