The HP-28C and HP-28S were two graphing calculators produced by Hewlett-Packard from 1986 to 1992. The HP-28C was the first handheld calculator capable of solving equations symbolically. They were replaced by the HP 48 series of calculators, which grew from the menu-driven RPL programming language interface first introduced in these HP-28 series.
Two models were produced, the HP-28C came first in 1987 with 2 kilobytes of usable RAM, and was the first handheld calculator with a Computer Algebra System.[1] A year later, the more common HP-28S was released with 32 KB of RAM and a directory system for filing variables, functions, and programs. The HP-28C used a Saturn processor running at 640 kHz whereas the HP-28S used a custom chip containing an improved Saturn processor core codenamed Lewis and running at 1 MHz.
The HP-28C was the last HP model introduced with the suffix "C" in its model designation – a practice which HP had started with the HP-25C back in 1976.[citation needed] The "C" had distinguished those models as having continuous memory. However, by 1988 that capability had become so common on calculators that it was no longer a feature of distinction, as it was an assumed characteristic of all serious scientific and business calculators. So beginning with the HP-28S, HP-17B, HP-19B, and HP-27S, the feature suffix "C" was replaced with a class suffix which was more meaningful in the market: "S" for Scientific, "B" for Business, and later (in 1993) "G" for Graphic.
Designedit
Clamshelledit
The HP-28 calculators shared a flip-open ("clamshell") case. On the left side of the flip, there is an alphabetic keyboard (in alphabetic order). On the right was a typical scientific keyboard layout.
LCD displayedit
The display was a 137×32 LCDdot matrix, usually displaying four lines of information (3 stack/command lines, plus one softkey label line).
Lack of computer interfaceedit
Among the drawbacks of the HP-28 was the lack of a computer interface. This meant that stored information could only be entered through the keypad and not backed up.
Weak battery coveredit
This model (and the HP-19 series that used the same clamshell design and internals) had one design problem that affected many units: the springs inside the unit that made contact with its three N-sized batteries made a considerably strong force, and the notches on the case in which the lid edges slid were too thin and shallow. Even if the case itself was sturdy enough, those notches were under extreme pressure, most especially while the user was opening or closing the lid (such as during the replacement of the batteries). As the lid edges were made of a harder metal, the plastic notches in the case were prone to cracking or breaking, even in carefully kept devices.[2] Surviving examples of the earlier versions of this calculator frequently have rubber bands around or tape over the cover to hold it in place (including the image attached to this article). This defect was later remedied on the HP-19BII, by putting the battery cover underneath the chassis.
Emulatorsedit
RPN 28x Calc -- A scientific calculator with a nostalgic, HP-28S-like interface for iPad
HP-28S Advanced Scientific Calculator Owner's Manual(PDF) (4 ed.). Hewlett-Packard. November 1988 [November 1987]. HP 00028-90066. (PDF) from the original on 2015-06-08. Retrieved 2016-08-07.
HP-28S Advanced Scientific Calculator Reference Manual(PDF) (4 ed.). Hewlett-Packard. November 1988 [October 1987]. HP 00028-90068. (PDF) from the original on 2015-06-08. Retrieved 2015-10-10.
HP 82240A Infrared Printer(PDF) (2 ed.). Corvallis, OR, USA: Hewlett-Packard, Portable Computer Division. October 1986. HP reorder number 82240-90001 (82240-90008). (PDF) from the original on 2016-08-06. Retrieved 2016-08-06.
(1 ed.). Corvallis, OR, USA: Hewlett-Packard. August 1989. HP reorder number 82240-90014. Archived from the original on 2016-08-14. Retrieved 2016-08-01.
Courbis, Paul; Lalande, Sébastien (2006-06-27) [1989]. Voyage au centre de la HP28c/s (in French) (2 ed.). Paris, France: Editions de la Règle à Calcul. OCLC 636072913. from the original on 2016-08-06. Retrieved 2015-09-06. [1][2][3][4][5][6]
Wickes, William C. (1988). HP-28 Insights: Principles and Programming of the HP-28C/S. Corvallis, Oregon: Larken Publications. ISBN0-9625258-1-2.
Wickes, William C. (January–February 1987). "The HP-28C: An Insider's Perspective". HPX Exchange. 1 (1).
External linksedit
HP-28 at the HP Calculator Museum
HP-28S pictures on MyCalcDB (database about 1970s and 1980s pocket calculators)
HP-28 from Tony's Taschenrechner-Sammlung Calculator-Collection
The HP28 WWW Archive
December 12, 2023
series, were, graphing, calculators, produced, hewlett, packard, from, 1986, 1992, first, handheld, calculator, capable, solving, equations, symbolically, they, were, replaced, series, calculators, which, grew, from, menu, driven, programming, language, interf. The HP 28C and HP 28S were two graphing calculators produced by Hewlett Packard from 1986 to 1992 The HP 28C was the first handheld calculator capable of solving equations symbolically They were replaced by the HP 48 series of calculators which grew from the menu driven RPL programming language interface first introduced in these HP 28 series HP 28S Contents 1 History 2 Design 2 1 Clamshell 2 2 LCD display 2 3 Lack of computer interface 2 4 Weak battery cover 3 Emulators 4 See also 5 References 6 Further reading 7 External linksHistory editTwo models were produced the HP 28C came first in 1987 with 2 kilobytes of usable RAM and was the first handheld calculator with a Computer Algebra System 1 A year later the more common HP 28S was released with 32 KB of RAM and a directory system for filing variables functions and programs The HP 28C used a Saturn processor running at 640 kHz whereas the HP 28S used a custom chip containing an improved Saturn processor core codenamed Lewis and running at 1 MHz The HP 28C was the last HP model introduced with the suffix C in its model designation a practice which HP had started with the HP 25C back in 1976 citation needed The C had distinguished those models as having continuous memory However by 1988 that capability had become so common on calculators that it was no longer a feature of distinction as it was an assumed characteristic of all serious scientific and business calculators So beginning with the HP 28S HP 17B HP 19B and HP 27S the feature suffix C was replaced with a class suffix which was more meaningful in the market S for Scientific B for Business and later in 1993 G for Graphic Design editClamshell edit The HP 28 calculators shared a flip open clamshell case On the left side of the flip there is an alphabetic keyboard in alphabetic order On the right was a typical scientific keyboard layout LCD display edit The display was a 137 32 LCD dot matrix usually displaying four lines of information 3 stack command lines plus one softkey label line Lack of computer interface edit Among the drawbacks of the HP 28 was the lack of a computer interface This meant that stored information could only be entered through the keypad and not backed up Weak battery cover edit This model and the HP 19 series that used the same clamshell design and internals had one design problem that affected many units the springs inside the unit that made contact with its three N sized batteries made a considerably strong force and the notches on the case in which the lid edges slid were too thin and shallow Even if the case itself was sturdy enough those notches were under extreme pressure most especially while the user was opening or closing the lid such as during the replacement of the batteries As the lid edges were made of a harder metal the plastic notches in the case were prone to cracking or breaking even in carefully kept devices 2 Surviving examples of the earlier versions of this calculator frequently have rubber bands around or tape over the cover to hold it in place including the image attached to this article This defect was later remedied on the HP 19BII by putting the battery cover underneath the chassis Emulators editRPN 28x Calc A scientific calculator with a nostalgic HP 28S like interface for iPad Halcyon Calc for iPhone iPod Touch and iPadSee also editHP calculators Comparison of HP graphing calculators Graphing calculator HP 82240A character set Modified HP Roman 8 References edit Nelson Richard J 2010 Hewlett Packard Calculator Firsts Hewlett Packard Development Company L P Archived from the original on 2010 07 03 HP28S ganjatron net Retrieved 2015 09 13 Further reading editHP 28S Advanced Scientific Calculator Owner s Manual PDF 4 ed Hewlett Packard November 1988 November 1987 HP 00028 90066 Archived PDF from the original on 2015 06 08 Retrieved 2016 08 07 HP 28S Advanced Scientific Calculator Reference Manual PDF 4 ed Hewlett Packard November 1988 October 1987 HP 00028 90068 Archived PDF from the original on 2015 06 08 Retrieved 2015 10 10 HP 82240A Infrared Printer PDF 2 ed Corvallis OR USA Hewlett Packard Portable Computer Division October 1986 HP reorder number 82240 90001 82240 90008 Archived PDF from the original on 2016 08 06 Retrieved 2016 08 06 HP 82240B Infrared Printer 1 ed Corvallis OR USA Hewlett Packard August 1989 HP reorder number 82240 90014 Archived from the original on 2016 08 14 Retrieved 2016 08 01 Courbis Paul Lalande Sebastien 2006 06 27 1989 Voyage au centre de la HP28c s in French 2 ed Paris France Editions de la Regle a Calcul OCLC 636072913 Archived from the original on 2016 08 06 Retrieved 2015 09 06 1 2 3 4 5 6 Wickes William C 1988 HP 28 Insights Principles and Programming of the HP 28C S Corvallis Oregon Larken Publications ISBN 0 9625258 1 2 Wickes William C January February 1987 The HP 28C An Insider s Perspective HPX Exchange 1 1 7 External links editHP 28 at the HP Calculator Museum HP 28S pictures on MyCalcDB database about 1970s and 1980s pocket calculators HP 28 from Tony s Taschenrechner Sammlung Calculator Collection The HP28 WWW Archive Retrieved from https en wikipedia org w index php title HP 28 series amp oldid 1178926415, wikipedia, wiki, book, books, library,
