The Motorola 68020 is a 32-bit microprocessor from Motorola, released in 1984. It is the successor to the Motorola 68010 and is succeeded by the Motorola 68030. A lower cost version was made available, known as the 68EC020. In keeping with naming practices common to Motorola designs, the 68020 is referred to as the "020", pronounced "oh-two-oh" or "oh-twenty"; the 68020 had 32-bit internal and external data and address buses, compared to the early 680x0 models with 16-bit data and 24-bit address buses. The 68020's ALU was natively 32-bit, so could perform 32-bit operations in one clock cycle, whereas the 68000 took a minimum of two clock cycles due to its 16-bit ALU. Newer packaging methods allowed the'020 to feature more external pins without the large size that the earlier dual in-line package method required; the 68EC020 lowered cost through a 24-bit address bus. The 68020 was produced at speeds ranging from 12 MHz to 33 MHz; the 68020 added many improvements over the 68010 including a 32-bit arithmetic logic unit, 32-bit external data and address buses, extra instructions and additional addressing modes.
The 68020 had a proper three-stage pipeline. Though the 68010 had a "loop mode", which sped loops through what was a tiny instruction cache, it held only two short instructions and was thus little used; the 68020 replaced this with a proper instruction cache of 256 bytes, the first 68k series processor to feature true on-chip cache memory. The previous 68000 and 68010 processors could only access word and long word data in memory if it were word-aligned; the 68020 had no alignment restrictions on data access. Unaligned accesses were slower than aligned accesses because they required an extra memory access; the 68020 has a coprocessor interface supporting up to eight coprocessors. The main CPU recognizes "F-line" instructions, uses special bus cycles to interact with a coprocessor to execute these instructions. Two types of coprocessors were defined: the paged memory management unit. Only one PMMU can be used with a CPU. In principle, multiple FPUs could be used with a CPU, but it was not done; the coprocessor interface is asynchronous, so it is possible to run the coprocessors at a different clock rate than the CPU.
Multiprocessing support was implemented externally by the use of a RMC pin to indicate an indivisible read-modify-write cycle in progress. All other processors had to hold off memory accesses. Software support for multiprocessing included the CAS and CAS2 instructions. In a multiprocessor system, coprocessors could not be shared between CPUs. To avoid problems with returns from coprocessor, bus error, address error exceptions, it was necessary in a multiprocessor system for all CPUs to be the same model, for all FPUs to be the same model as well; the new instructions included some minor improvements and extensions to the supervisor state, several instructions for software management of a multiprocessing system, some support for high-level languages which did not get used much, bigger multiply and divide instructions, bit field manipulations. While the 68000 had'supervisor mode', it did not meet the Popek and Goldberg virtualization requirements due to the single instruction'MOVE from SR' being unprivileged but sensitive.
Under the 68010 and this was made privileged, to better support virtualization software. The new addressing modes added scaled indexing and another level of indirection to many of the pre-existing modes, added quite a bit of flexibility to various indexing modes and operations. Though it was not intended, these new modes made the 68020 suitable for page printing; the 68020 had a small 256-byte direct-mapped instruction cache, arranged as 64 four-byte entries. Although small, it still made a significant difference in the performance of many applications; the resulting decrease in bus traffic was important in systems relying on DMA. The 68020 was used in the Apple Macintosh II and Macintosh LC personal computers, Sun 3 workstations, Commodore Amiga 1200, the Hewlett-Packard 8711 Series Network Analyzers and members of the HP 9000/300 family and the Alpha Microsystems AM-2000; the 68020 was an alternative upgrade to the Sinclair QL computer's 68008 in the Super Gold Card interface by Miracle Systems.
The Amiga 2500 and A2500UX was shipped with the A2620 Accelerator using a 68020, a 68881 floating point unit and the 68851 Memory Management Unit. The 2500UX shipped with Amiga Unix, requiring an'020 or'030 processor. A number of digital oscilloscopes from the mid-80s to the late-90s used the 68020, including the LeCroy 9300 Series and the earlier LeCroy 9400 series, along with certain Tektronix TDS Series models.. The HP 54520, 54522, 54540 and 54542 use the 68020, together with a 68882 math coprocessor, it is the processor used on board TGV trains to decode signalling information, sent to the trains through the rails. It is further being used in the flight control and radar systems of the Eurofighter Typhoon combat aircraft; the Nortel Networks DMS-100 telephone central office swit
Ethipothala Falls is a 70 feet high river cascade, situated in Guntur district, Andhra Pradesh, India. Located on the Chandravanka river, a tributary of River Krishna joining on its right bank; the waterfall is a combination of three streams namely Chandravanka Vagu, Nakkala Vagu and Tummala Vagu. It is situated about 11 kilometres from Nagarjuna Sagar Dam; the river joins the Krishna river after the dam after travelling about 3 kilometres from the falls. A strategic view point was created by the Andhra Pradesh Tourism Department from the adjacent hillock. There is a crocodile breeding centre in the pond formed by the waterfall. Water from the Nagarjuna Sagar right bank canal is released in to the above streams to keep the waterfall alive and flowing throughout the year for tourism purposes; this place has a huge spiritual significance, it is a place where there is a temple of Lord Dattatreya with Ekamukhi. The Lord Datta here is the main worship god for Lambadi Tribal people around this place.
They will offer prayers and sevas to him without knowing any mantras. The waterfall is a combination of three streams namely, the Chandra Vanka stream on Macherla, Surya bhaga stream on Nagarjuna hill and Krishna river of Nagarjuna sagar. Hence, it is like a Triveni sangama; the sight of the waterfalls as it cascades down a number of steps is a wonderful sight after the monsoons. Just adjacent to the falls is located Datta Guru's Temple; the Datta idol can be visualized in a blissfully intoxicated state–the gross parallel state. Below the hillock is the Madhumathy Devi Alayam; the Uttaranga mantras for Anushtup are Madhumati Mahavidya and Sri Datta Sahasrakshari It is rare to find such a Mandira wherein both Lord Dattatreya and Goddess Madhumathy devi are together. Yoga lakshmi devi is in the form of Madhumathi devi here; the rule here is that first one must have a Darshan of the Goddess and have Datta-darshana. In this kshetra, Dattaguru is fulfilling the desires in the form of Swapna, Sparsha and vachasa vidhana.
This kshetra is an ANANDA NILAYA for Paripoorna yoga. The form of Dattatreya in this kshetra is same as in Dhyana sloka of Dattatreya. Ethipothala is derived from "eththi", "potha" of the Telugu language which means to "lift and pour". Alternatively it could have been derived from "eththu" and "potha", meaning the downpour as in kundapotha, connoting the downpour of water from a great height. Incidentally the word ethipothala is terminology coined in Telugu for lift irrigation, it is a misnomer for people to assume. As far as Ethipothala Falls are concerned it has nothing to do with the government's "Ethipothala Padhakam"; the reasons for this confusion is because the administration and media in the state use the term "Ethipothala Padhakam" to refer to the Lift Irrigation Scheme. Both terms are related to water bodies such as rivers, canals etc. There is a major irrigation project named Nagarjuna Sagar located nearby Ethipothala Falls; this gives a scope for people to assume that these falls are part of that project, though that project does not concern the LIS
Sofia Reyes de Veyra was a Filipina feminist, clubwoman and school founder, president of the National Federation of Women's Clubs. Sofia Reyes was born in the daughter of Santiago Reyes and Eulalia Tiaozon. Sofia Reyes taught English as a young woman, she co-founded a nurses' training school at Iloilo City in 1907 with an American woman, Mary E. Coleman. In 1917, she moved to Washington D. C. as a diplomat's wife, while there gave lectures and was otherwise active in women's clubs. She wrote essays. In 1922 she was the Philippines' delegate to the Pan-Pacific conference held in Baltimore, she met with first lady Florence Harding, received a certificate of appreciation from the American Red Cross for her contributions during World War I. Sofia de Veyra was noted for wearing the distinctive Philippine terno formal dress to events and while giving public speeches in the United States. Back in the Philippines by 1925, she founded the Manila Women's Club. In time she became president of the National Federation of Women's Clubs, used her position to advocate for women's suffrage in the Philippines.
She was appointed head of the domestic science department at Centro Escolar de Señoritas, a girls' school. She co-wrote a cookbook, published in both English and Spanish, Everyday Cookery for the Home. Sofia Reyes married politician Jaime Carlos de Veyra in 1907, they had four children. Their son Manuel E. de Veyra was a doctor during World War II serving at Bataan. Their son Jesus de Veyra became a judge, dean of the Ateneo Law School from 1976 to 1981. Sofia Reyes de Veyra died in 1953, aged 77 years, her daughter-in-law wrote a biography, Work, Success: An Appraisal of the Life and Work of Sofia Reyes de Veyra, in 1959. There is a historical marker honoring de Veyra's work in her home district in the Western Visayas region