Question: Which software developed by Pito Salas was purchased by IBM in the 1990's?

Context paragraphs:
IBM Systems Application Architecture: Systems Application Architecture (SAA), introduced in 1987, is a set of standards for computer software developed by IBM.  The SAA initiative was started in 1987 under the leadership of Earl Wheeler, the "Father of SAA".  The intent was to implement SAA in IBM operating systems including MVS, OS/400 and OS/2.  AIX, IBM's version of the UNIX operating system, was not a target of SAA, but does have interoperability with the SAA family.

NetVault Backup: NetVault is a set of data protection software developed and supported by Quest Software.  NetVault Backup is a backup and recovery software product.  It can be used to protect data and software applications in physical and virtual environments from one central management interface.  It supports many servers, application platforms and protocols such as UNIX, Linux, Mac OS X, Microsoft Windows, VMware, Microsoft Hyper-V, Oracle, Sybase, Microsoft SQL Server, NDMP, Oracle ACSLS, IBM DAS/ACI, Microsoft Exchange Server, DB2, Informix, MySQL, IBM Domino, and Teradata.

IBM PCPG: IBM Personal Computer Picture Graphics (PCPG) is a software developed in BASIC by Eugene Ying in the 1980s, for the IBM PC operating system.

Lotus Software: Lotus Software (called Lotus Development Corporation before its acquisition by IBM) was an American software company based in Massachusetts.  Lotus is most commonly known for the Lotus 1-2-3 spreadsheet application, the first feature-heavy, user-friendly, reliable and WYSIWYG-enabled product to become widely available in the early days of the IBM PC, when there was no graphical user interface.  Much later, in conjunction with Ray Ozzie's Iris Associates, Lotus also released a groupware and email system, Lotus Notes.  IBM purchased the company in 1995 for US$3.5 billion, primarily to acquire Lotus Notes and to establish a presence in the increasingly important client–server computing segment, which was rapidly making host-based products such as IBM's OfficeVision obsolete.

Pito Salas: Pito Salas is a Curacaoan-American Cambridge, Massachusetts-based software developer.  While working with Lotus' Advanced Technology Group in 1986, Salas invented the pivot table, a "next-generation" spreadsheet concept which was released by Lotus in 1989 as Lotus Improv.

S2 Spreadsheet: S2 Spreadsheet was a Lotus 1-2-3 compatible spreadsheet developed by IBM in 1984.  It had all the features of Lotus 1-2-3, plus it had an ability to connect to IBM mainframes via TCP/IP and pull data from IBM databases such as IBM DB2 and IBM SQL/DS.  It also had features that allowed for easy visual connection between formulas and their dependencies - those features were later adopted by Lotus 1-2-3 and Microsoft Excel.  S2 was developed almost concurrently with Lotus development of 1-2-3, and matched 1-2-3 feature for feature.  The S2 program was used throughout IBM in 1980s and 1990s.  In 1986 it caused a legal controversy within IBM because of then current look-and-feel lawsuits between Lotus and other companies, and most importantly because IBM was negotiating a high-profile deal with Lotus to market Lotus 1-2-3.

Moneyspire: Moneyspire (formerly Fortora Fresh Finance) is personal finance software and small business accounting software developed by Moneyspire Inc.  The software is available in two versions, one for Windows and another for macOS.  The software tracks accounts, loans, bills, investments and budgets.  Professional looking invoices can also be created and tracked in the Pro edition of Moneyspire.  It imports data from QIF, OFX, QFX and CSV files.  Moneyspire has the ability to use its financial data files interchangeably between the Mac and Windows versions of the software, thus making the software a viable choice for people who use both PCs and Macs.  Moneyspire can also manage accounts from multiple currencies, and automatically track exchange rates and transfers between foreign accounts.

IBM BigFix: IBM BigFix formerly IBM Endpoint Manager, Tivoli Endpoint Manager (TEM) and before that, BigFix, is a systems-management software product developed by IBM for managing large groups of computers running Windows, Mac OS X, VMware ESX, Linux or UNIX, as well as various mobile operating systems such as Windows Phone, Symbian, iOS and Android.  IBM Endpoint Manager provides system administrators with remote control, patch management, software distribution, operating system deployment, network access protection and hardware and software inventory functionality.

ILOG: ILOG was an international software company purchased and incorporated into IBM announced in January, 2009.  It created enterprise software products for supply chain, business rule management, visualization and optimization.  The main product line for Business Rules Management Systems (BRMS) has been rebranded as IBM Operational Decision Manager (ODM).  Many of the related components retain the ILOG brand as a part of their name.  See IBM Corporate link below for more details.  The software developed by the ILOG software company supports several software platforms, including COBOL, C++, C#, . NET, Java, AJAX and Adobe Flex / AIR.

Definitive software library: A definitive software library (DSL) is a secure location, consisting of physical media or a software repository located on a network file server, in which the definitive authorized versions of all software configuration items (CIs) are stored and protected.  The DSL is separate from development, quality assurance or production software storage areas.  It contains master copies of all controlled software and includes definitive copies of purchased software, as well as licensing information for software developed on-site or purchased from an external vendor.  All related documentation, related to any software stored in the DSL, is also stored in the DSL.

Supporting paragraphs: Pito Salas Lotus Software
Answer: Lotus Software